diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index 28e04ad8d7..6e46def0fc 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -58,7 +58,7 @@ jobs:
       matrix:
         os:
           - 'ubuntu-18.04'
-#          - 'windows-2019'
+          - 'windows-2019'
           - 'macos-10.15'
         python:
           - '3.6'
diff --git a/.github/workflows/release_test.yml b/.github/workflows/release_test.yml
index 0fcbe57e25..61d714fa8c 100644
--- a/.github/workflows/release_test.yml
+++ b/.github/workflows/release_test.yml
@@ -49,7 +49,7 @@ jobs:
       matrix:
         os:
           - 'ubuntu-18.04'
-#          - 'windows-2019'
+          - 'windows-2019'
           - 'macos-10.15'
         python:
           - '3.6'
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 309b23aa22..013659ea42 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -18,7 +18,7 @@ jobs:
       matrix:
         os:
           - 'ubuntu-18.04'
-          # - 'windows-2019'  # need to be fixed, see: https://github.com/opendilab/treevalue/issues/41
+          - 'windows-2019'  # need to be fixed, see: https://github.com/opendilab/treevalue/issues/41
           - 'macos-10.15'
         python-version:
           - '3.6'
@@ -29,21 +29,21 @@ jobs:
 
     steps:
       - name: Get system version for Linux
-        if: ${{ contains(matrix.os, 'ubuntu') }}
+        if: ${{ runner.os == 'Linux' }}
         shell: bash
         run: |
           echo "OS_NAME=Linux" >> $GITHUB_ENV
           echo "IS_WIN=" >> $GITHUB_ENV
           echo "IS_MAC=" >> $GITHUB_ENV
       - name: Get system version for Windows
-        if: ${{ contains(matrix.os, 'windows') }}
+        if: ${{ runner.os == 'Windows' }}
         shell: bash
         run: |
           echo "OS_NAME=Windows" >> $GITHUB_ENV
           echo "IS_WIN=1" >> $GITHUB_ENV
           echo "IS_MAC=" >> $GITHUB_ENV
       - name: Get system version for MacOS
-        if: ${{ contains(matrix.os, 'macos') }}
+        if: ${{ runner.os == 'macOS' }}
         shell: bash
         run: |
           echo "OS_NAME=MacOS" >> $GITHUB_ENV
diff --git a/pyproject.toml b/pyproject.toml
index f0742e0f17..1cb4bff966 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -8,11 +8,23 @@ requires = [
 [tool.cibuildwheel]
 skip = ["pp*"] # Do not build for PyPy
 
+## Windows build configuration
+[tool.cibuildwheel.windows]
+archs = ["x86", 'AMD64']
+before-test = [# Unittest for windows
+    "pip install -r \"{project}\\requirements-test-win.txt\"",
+]
+test-command = [
+    "xcopy /e /i \"{project}\\test\" test",
+    "copy \"{project}\\pytest.ini\" pytest.ini",
+    "pytest test -sv -m unittest --log-level=DEBUG",
+    "rmdir /s /q test",
+]
 
 ## macOS build configuration
 [tool.cibuildwheel.macos]
 archs = ["x86_64", "arm64"] # Build for x86_64 and arm64
-before-test = [# Unittest for linux
+before-test = [# Unittest for macos
     "pip install -r {project}/requirements-test.txt",
 ]
 test-command = [
diff --git a/requirements-test-win.txt b/requirements-test-win.txt
new file mode 100644
index 0000000000..eab8a2433b
--- /dev/null
+++ b/requirements-test-win.txt
@@ -0,0 +1,15 @@
+coverage>=5
+mock>=4.0.3
+flake8~=3.5
+pytest~=6.2.5
+pytest-cov~=3.0.0
+pytest-mock~=3.6.1
+pytest-xdist>=1.34.0
+pytest-rerunfailures~=10.2
+pytest-timeout~=2.0.2
+pytest-benchmark~=3.4.0
+testtools>=2
+hbutils>=0.6.13
+setuptools<=59.5.0
+numpy>=1.10
+easydict>=1.7,<2
\ No newline at end of file
diff --git a/test/entry/cli/test_export.py b/test/entry/cli/test_export.py
index 907c79d240..2eef7f2927 100644
--- a/test/entry/cli/test_export.py
+++ b/test/entry/cli/test_export.py
@@ -30,7 +30,8 @@ def test_simple_export(self):
         with runner.isolated_filesystem():
             result = runner.invoke(treevalue_cli, ['export', '-t', 'test.entry.cli.test_export.t1'])
 
-            assert result.exit_code == 0
+            assert result.exit_code == 0, f'Runtime Error (exitcode {result.exit_code}), ' \
+                                          f'The output is:\n{result.output}'
             assert os.path.exists('t1.btv')
             assert os.path.getsize('t1.btv') < 240
 
@@ -42,7 +43,8 @@ def test_multiple_export(self):
         with runner.isolated_filesystem():
             result = runner.invoke(treevalue_cli, ['export', '-t', 'test.entry.cli.test_export.*'])
 
-            assert result.exit_code == 0
+            assert result.exit_code == 0, f'Runtime Error (exitcode {result.exit_code}), ' \
+                                          f'The output is:\n{result.output}'
             assert os.path.exists('t1.btv')
             assert os.path.getsize('t1.btv') < 240
             assert os.path.exists('t2.btv')
@@ -60,7 +62,8 @@ def test_multiple_export(self):
         with runner.isolated_filesystem():
             result = runner.invoke(treevalue_cli, ['export', '-t', 'test.entry.cli.test_export.t[23]'])
 
-            assert result.exit_code == 0
+            assert result.exit_code == 0, f'Runtime Error (exitcode {result.exit_code}), ' \
+                                          f'The output is:\n{result.output}'
             assert not os.path.exists('t1.btv')
             assert os.path.exists('t2.btv')
             assert os.path.getsize('t2.btv') < 290
@@ -78,7 +81,8 @@ def test_multiple_export_without_compression(self):
             with pytest.warns(None):
                 result = runner.invoke(treevalue_cli, ['export', '-t', 'test.entry.cli.test_export.*', '-r'])
 
-            assert result.exit_code == 0
+            assert result.exit_code == 0, f'Runtime Error (exitcode {result.exit_code}), ' \
+                                          f'The output is:\n{result.output}'
             assert os.path.exists('t1.btv')
             assert os.path.getsize('t1.btv') < 2170
             assert os.path.exists('t2.btv')
@@ -98,7 +102,8 @@ def test_multiple_export_without_compression(self):
                 result = runner.invoke(treevalue_cli, ['export', '-t', 'test.entry.cli.test_export.*',
                                                        '-r', '-c', 'zlib'])
 
-            assert result.exit_code == 0
+            assert result.exit_code == 0, f'Runtime Error (exitcode {result.exit_code}), ' \
+                                          f'The output is:\n{result.output}'
             assert os.path.exists('t1.btv')
             assert os.path.getsize('t1.btv') < 2170
             assert os.path.exists('t2.btv')
@@ -119,7 +124,8 @@ def test_multiple_export_with_compress_define(self):
             result = runner.invoke(treevalue_cli, ['export', '-t', 'test.entry.cli.test_export.*',
                                                    '-c', 'gzip'])
 
-            assert result.exit_code == 0
+            assert result.exit_code == 0, f'Runtime Error (exitcode {result.exit_code}), ' \
+                                          f'The output is:\n{result.output}'
             assert os.path.exists('t1.btv')
             assert os.path.getsize('t1.btv') < 220
             assert os.path.exists('t2.btv')
@@ -140,7 +146,8 @@ def test_multiple_export_with_compress_define(self):
                 '-c', 'test.entry.cli.test_export._my_compress:test.entry.cli.test_export._my_decompress'
             ])
 
-            assert result.exit_code == 0
+            assert result.exit_code == 0, f'Runtime Error (exitcode {result.exit_code}), ' \
+                                          f'The output is:\n{result.output}'
             assert os.path.exists('t1.btv')
             assert os.path.getsize('t1.btv') < 330
             assert os.path.exists('t2.btv')
@@ -167,7 +174,8 @@ def test_with_od(self):
                     '-o', 'subpath/t3.btv',
                 ])
 
-            assert result.exit_code == 0
+            assert result.exit_code == 0, f'Runtime Error (exitcode {result.exit_code}), ' \
+                                          f'The output is:\n{result.output}'
             assert os.path.exists('subpath/t1.btv')
             assert os.path.getsize('subpath/t1.btv') < 290
             assert os.path.exists('subpath/t2.btv')
@@ -190,7 +198,8 @@ def test_with_od(self):
                     '-d', 'subpath',
                 ])
 
-            assert result.exit_code == 0
+            assert result.exit_code == 0, f'Runtime Error (exitcode {result.exit_code}), ' \
+                                          f'The output is:\n{result.output}'
             assert os.path.exists('subpath/t1.btv')
             assert os.path.getsize('subpath/t1.btv') < 290
             assert os.path.exists('subpath/t2.btv')
@@ -210,7 +219,8 @@ def test_with_od(self):
                     '-d', 'subpath',
                 ])
 
-            assert result.exit_code == 0
+            assert result.exit_code == 0, f'Runtime Error (exitcode {result.exit_code}), ' \
+                                          f'The output is:\n{result.output}'
             assert not os.path.exists('subpath/t1.btv')
             assert os.path.exists('subpath/t2.btv')
             assert os.path.getsize('subpath/t2.btv') < 290
@@ -229,7 +239,8 @@ def test_with_od(self):
                     '-o', 'ppp.btv'
                 ])
 
-            assert result.exit_code == 0
+            assert result.exit_code == 0, f'Runtime Error (exitcode {result.exit_code}), ' \
+                                          f'The output is:\n{result.output}'
             assert not os.path.exists('t1.btv')
             assert not os.path.exists('t2.btv')
             assert os.path.exists('ppp.btv')
diff --git a/test/entry/cli/test_graph.py b/test/entry/cli/test_graph.py
index 9fe6bdfec5..a88b2a636c 100644
--- a/test/entry/cli/test_graph.py
+++ b/test/entry/cli/test_graph.py
@@ -7,7 +7,7 @@
 
 import pytest
 from click.testing import CliRunner
-from hbutils.testing import cmdv
+from hbutils.testing import cmdv, OS
 
 from treevalue import FastTreeValue, dump, graphics
 from treevalue.entry.cli import treevalue_cli
@@ -36,7 +36,8 @@ def test_simple_code_graph(self):
                       '-o', 'test_graph.svg', '-o', 'test_graph.gv'],
             )
 
-            assert result.exit_code == 0
+            assert result.exit_code == 0, f'Runtime Error (exitcode {result.exit_code}), ' \
+                                          f'The output is:\n{result.output}'
             assert os.path.exists('test_graph.svg')
             assert os.path.getsize('test_graph.svg') <= 7000
             assert os.path.exists('test_graph.gv')
@@ -52,7 +53,8 @@ def test_simple_code_graph_to_stdout(self):
                           '-o', 'test_graph.svg', '-o', 'test_graph.gv', '-O'],
                 )
 
-            assert result.exit_code == 0
+            assert result.exit_code == 0, f'Runtime Error (exitcode {result.exit_code}), ' \
+                                          f'The output is:\n{result.output}'
             assert not os.path.exists('test_graph.svg')
             assert not os.path.exists('test_graph.gv')
             assert len(result.output) <= 2500
@@ -66,7 +68,8 @@ def test_simple_code_multiple_graph(self):
                 args=['graph', '-t', 'test.entry.cli.test_graph.t[12]', '-o', 'test_graph.svg'],
             )
 
-            assert result.exit_code == 0
+            assert result.exit_code == 0, f'Runtime Error (exitcode {result.exit_code}), ' \
+                                          f'The output is:\n{result.output}'
             assert os.path.exists('test_graph.svg')
             assert os.path.getsize('test_graph.svg') <= 13000
 
@@ -76,7 +79,8 @@ def test_simple_code_multiple_graph(self):
                 args=['graph', '-t', 'test.entry.cli.test_graph.*', '-o', 'test_graph.svg'],
             )
 
-            assert result.exit_code == 0
+            assert result.exit_code == 0, f'Runtime Error (exitcode {result.exit_code}), ' \
+                                          f'The output is:\n{result.output}'
             assert os.path.exists('test_graph.svg')
             assert os.path.getsize('test_graph.svg') <= 17500
 
@@ -92,7 +96,8 @@ def test_simple_binary_graph(self):
                 args=['graph', '-t', 'g1.bg', '-o', 'test_graph.svg'],
             )
 
-            assert result.exit_code == 0
+            assert result.exit_code == 0, f'Runtime Error (exitcode {result.exit_code}), ' \
+                                          f'The output is:\n{result.output}'
             assert os.path.exists('test_graph.svg')
             assert os.path.getsize('test_graph.svg') <= 6500
 
@@ -109,7 +114,8 @@ def test_simple_binary_graph(self):
                 args=['graph', '-t', '*.bg', '-o', 'test_graph.svg'],
             )
 
-            assert result.exit_code == 0
+            assert result.exit_code == 0, f'Runtime Error (exitcode {result.exit_code}), ' \
+                                          f'The output is:\n{result.output}'
             assert os.path.exists('test_graph.svg')
             assert os.path.getsize('test_graph.svg') <= 17500
 
@@ -122,7 +128,8 @@ def test_simple_binary_graph(self):
                 args=['graph', '-t', 'test.entry.cli.test_graph.t1', '-o', 'test_graph.svg'],
             )
 
-            assert result.exit_code == 0
+            assert result.exit_code == 0, f'Runtime Error (exitcode {result.exit_code}), ' \
+                                          f'The output is:\n{result.output}'
             assert os.path.exists('test_graph.svg')
             assert os.path.getsize('test_graph.svg') <= 13000
 
@@ -135,7 +142,8 @@ def test_simple_binary_graph(self):
                 args=['graph', '-t', 'test.entry.cli.test_graph.t1', '-o', 'test_graph.svg'],
             )
 
-            assert result.exit_code == 0
+            assert result.exit_code == 0, f'Runtime Error (exitcode {result.exit_code}), ' \
+                                          f'The output is:\n{result.output}'
             assert os.path.exists('test_graph.svg')
             assert os.path.getsize('test_graph.svg') <= 6500
 
@@ -149,7 +157,8 @@ def test_duplicates(self):
                       '-o', 'test_graph.svg'],
             )
 
-            assert result.exit_code == 0
+            assert result.exit_code == 0, f'Runtime Error (exitcode {result.exit_code}), ' \
+                                          f'The output is:\n{result.output}'
             assert os.path.exists('test_graph.svg')
             assert os.path.getsize('test_graph.svg') <= 12000
 
@@ -162,7 +171,8 @@ def test_duplicates(self):
                       '-o', 'test_graph.svg'],
             )
 
-            assert result.exit_code == 0
+            assert result.exit_code == 0, f'Runtime Error (exitcode {result.exit_code}), ' \
+                                          f'The output is:\n{result.output}'
             assert os.path.exists('test_graph.svg')
             import shutil
             shutil.copy('test_graph.svg', os.path.join(_p, 'test_graph.svg'))
@@ -179,7 +189,8 @@ def test_graph(self):
                           '-t', 'first title', '-o', 'test_graph.svg'],
                 )
 
-            assert result.exit_code == 0
+            assert result.exit_code == 0, f'Runtime Error (exitcode {result.exit_code}), ' \
+                                          f'The output is:\n{result.output}'
             assert os.path.exists('test_graph.svg')
             assert os.path.getsize('test_graph.svg') <= 16500
 
@@ -196,7 +207,8 @@ def test_cfg(self):
                       '-c', 'bgcolor=#ffffff00', '-O'],
             )
 
-            assert result.exit_code == 0
+            assert result.exit_code == 0, f'Runtime Error (exitcode {result.exit_code}), ' \
+                                          f'The output is:\n{result.output}'
             assert len(result.output) <= 6000
             assert '#ffffff00' in result.output
 
@@ -207,7 +219,9 @@ def test_cfg(self):
                       '-c', 'bgcolor#ffffff00', '-O'],
             )
 
-            assert result.exit_code != 0
+            assert result.exit_code != 0, f'The running expected to raise RuntimeError ' \
+                                          f'but not actually (exitcode {result.exit_code}), ' \
+                                          f'The output is:\n{result.output}'
             assert "Configuration should be KEY=VALUE, but 'bgcolor#ffffff00' found." in result.output
 
     @unittest.skipUnless(cmdv('dot'), 'Dot installed only')
@@ -227,6 +241,10 @@ def test_file_with_invalid_permission(self):
                     args=['graph', '-t', 'g1.bg', '-o', 'test_graph.svg'],
                 )
 
-                assert result.exit_code == 0
+                assert result.exit_code == 0, f'Runtime Error (exitcode {result.exit_code}), ' \
+                                              f'The output is:\n{result.output}'
                 assert os.path.exists('test_graph.svg')
-                assert os.path.getsize('test_graph.svg') <= 1000
+                if OS.windows:
+                    assert os.path.getsize('test_graph.svg') <= 2000
+                else:
+                    assert os.path.getsize('test_graph.svg') <= 1000
diff --git a/test/entry/cli/test_version.py b/test/entry/cli/test_version.py
index 8a5b3771b3..689be95f4f 100644
--- a/test/entry/cli/test_version.py
+++ b/test/entry/cli/test_version.py
@@ -11,6 +11,7 @@ def test_version(self):
         runner = CliRunner()
         result = runner.invoke(treevalue_cli, args=['-v'])
 
-        assert result.exit_code == 0
+        assert result.exit_code == 0, f'Runtime Error (exitcode {result.exit_code}), ' \
+                                      f'The output is:\n{result.output}'
         assert __TITLE__.lower() in result.stdout.lower()
         assert __VERSION__.lower() in result.stdout.lower()
diff --git a/test/tree/general/test_general_benchmark.py b/test/tree/general/test_general_benchmark.py
index 66ab359b85..88bbb64d91 100644
--- a/test/tree/general/test_general_benchmark.py
+++ b/test/tree/general/test_general_benchmark.py
@@ -1,19 +1,36 @@
+import unittest
+from functools import lru_cache
+from typing import Optional
+
+from hbutils.testing import vpip
+
+try:
+    import torch
+except ImportError:
+    torch = None
+
 import pytest
-import torch
 
 from treevalue import TreeValue, func_treelize, FastTreeValue
 
-_TREE_DATA_1 = {'a': torch.randn(2, 3), 'x': {'c': torch.randn(3, 4)}}
-_TREE_1 = FastTreeValue(_TREE_DATA_1)
+
+@lru_cache()
+def _get_tree() -> Optional[FastTreeValue]:
+    if torch is not None:
+        _TREE_DATA_1 = {'a': torch.randn(2, 3), 'x': {'c': torch.randn(3, 4)}}
+        return FastTreeValue(_TREE_DATA_1)
+    else:
+        return None
 
 
 @pytest.mark.benchmark(group='treevalue_dynamic')
+@unittest.skipUnless(vpip('torch') >= '1.1.0', 'Torch>=1.1.0 only')
 class TestTreeGeneralBenchmark:
     def test_dynamic_execute(self, benchmark):
         def sin(t):
             return t.sin()
 
-        return benchmark(sin, _TREE_1)
+        return benchmark(sin, _get_tree())
 
     def test_static_execute(self, benchmark):
         sinf = func_treelize(return_type=TreeValue)(torch.sin)
@@ -21,4 +38,4 @@ def test_static_execute(self, benchmark):
         def sin(t):
             return sinf(t)
 
-        return benchmark(sin, _TREE_1)
+        return benchmark(sin, _get_tree())
diff --git a/test/tree/general/test_tensor.py b/test/tree/general/test_tensor.py
index 26a462d5b4..2574ab322d 100644
--- a/test/tree/general/test_tensor.py
+++ b/test/tree/general/test_tensor.py
@@ -1,10 +1,18 @@
+import unittest
+
 import pytest
-import torch
+from hbutils.testing import vpip
+
+try:
+    import torch
+except ImportError:
+    torch = None
 
 from treevalue.tree import func_treelize, FastTreeValue
 
 
 @pytest.mark.unittest
+@unittest.skipUnless(vpip('torch') >= '1.1.0', 'Torch>=1.1.0 only')
 def test_for_torch_support():
     sin = func_treelize()(torch.sin)
     cos = func_treelize()(torch.cos)  # the same sin function
diff --git a/test/utils/test_formattree.py b/test/utils/test_formattree.py
index 89e1fa3c0a..f970ac1dc5 100644
--- a/test/utils/test_formattree.py
+++ b/test/utils/test_formattree.py
@@ -19,6 +19,8 @@
 # And in this library 'treevalue', Apache Licence Version 2.0 is used as well.
 
 import doctest
+import io
+import os
 from operator import itemgetter
 from textwrap import dedent
 
@@ -31,6 +33,11 @@
 )
 
 
+def _process_linesep(s: str) -> str:
+    with io.StringIO(s) as sf:
+        return os.linesep.join([line.rstrip('\r\n') for line in sf])
+
+
 @pytest.mark.unittest
 class TestFormatTree(TestCase):
 
@@ -40,9 +47,9 @@ def format_tree(self, tree, encoding='utf8'):
     def test_single_node_tree(self):
         tree = ('foo', [])
         output = self.format_tree(tree)
-        self.assertEqual(dedent(u'''\
+        self.assertEqual(_process_linesep(dedent(u'''\
         foo
-        '''), output)
+        ''')), _process_linesep(output))
 
     def test_single_level_tree(self):
         tree = (
@@ -53,12 +60,12 @@ def test_single_level_tree(self):
             ],
         )
         output = self.format_tree(tree)
-        self.assertEqual(dedent(u'''\
+        self.assertEqual(_process_linesep(dedent(u'''\
         foo
         ├── bar
         ├── baz
         └── qux
-        '''), output)
+        ''')), _process_linesep(output))
 
     def test_single_level_tree_with_ascii(self):
         tree = (
@@ -69,12 +76,12 @@ def test_single_level_tree_with_ascii(self):
             ],
         )
         output = self.format_tree(tree, encoding='ascii')
-        self.assertEqual(dedent(u'''\
+        self.assertEqual(_process_linesep(dedent(u'''\
         foo
         +-- bar
         +-- baz
         `-- qux
-        '''), output)
+        ''')), _process_linesep(output))
 
     def test_multi_level_tree(self):
         tree = (
@@ -88,14 +95,14 @@ def test_multi_level_tree(self):
             ],
         )
         output = self.format_tree(tree)
-        self.assertEqual(dedent(u'''\
+        self.assertEqual(_process_linesep(dedent(u'''\
         foo
         ├── bar
         │   ├── a
         │   └── b
         ├── baz
         └── qux
-        '''), output)
+        ''')), _process_linesep(output))
 
     def test_multi_level_on_last_node_tree(self):
         tree = (
@@ -109,14 +116,14 @@ def test_multi_level_on_last_node_tree(self):
             ],
         )
         output = self.format_tree(tree)
-        self.assertEqual(dedent(u'''\
+        self.assertEqual(_process_linesep(dedent(u'''\
         foo
         ├── bar
         ├── baz
         └── qux
             ├── a
             └── b
-        '''), output)
+        ''')), _process_linesep(output))
 
     def test_acceptance(self):
         output = self.format_tree(ACCEPTANCE_INPUT)
@@ -140,7 +147,7 @@ def test_newlines(self):
             ],
         )
         output = self.format_tree(tree)
-        self.assertEqual(dedent(u'''\
+        self.assertEqual(_process_linesep(dedent(u'''\
         foo
         ├── bar
         │   frob
@@ -151,7 +158,7 @@ def test_newlines(self):
         ├── baz
         └── qux
             frab
-        '''), output)
+        ''')), _process_linesep(output))
 
 
 def d(name, files):
diff --git a/treevalue/entry/cli/graph.py b/treevalue/entry/cli/graph.py
index 0c43e3d8c2..db45bc540f 100644
--- a/treevalue/entry/cli/graph.py
+++ b/treevalue/entry/cli/graph.py
@@ -1,7 +1,5 @@
 import codecs
 import os
-import shutil
-import tempfile
 import warnings
 from collections import OrderedDict
 from functools import partial
@@ -61,10 +59,7 @@ def _save_source_code(g: Digraph, path: str):
 
 
 def _save_image(g: Digraph, path: str, fmt: str):
-    with tempfile.TemporaryDirectory() as tmpdir:
-        with tempfile.NamedTemporaryFile(dir=tmpdir) as tmpfile:
-            svg_file = g.render(tmpfile.name, format=fmt)
-            shutil.copy(svg_file, path)
+    g.render(path, format=fmt)
 
 
 _IMAGE_FMTS = {'svg', 'png'}