diff --git a/scripts/phase0/build_spec.py b/scripts/phase0/build_spec.py
index 0dba32b17f..f50afc3d36 100644
--- a/scripts/phase0/build_spec.py
+++ b/scripts/phase0/build_spec.py
@@ -10,6 +10,7 @@ def build_phase0_spec(outfile, sourcefiles):
     Any,
     Dict,
     List,
+    Map,
     NewType,
     Tuple,
 )
@@ -39,10 +40,11 @@ def build_phase0_spec(outfile, sourcefiles):
 BLSSignature = NewType('BLSSignature', bytes)  # bytes96
 Store = None
 """)
-    for sourcefile in sourcefiles:
-        code_lines += function_puller.get_spec(sourcefile)
+    for index, sourcefile in enumerate(sourcefiles):
+        code_lines += function_puller.get_spec(sourcefile, index)
 
     code_lines.append("""
+
 # Monkey patch validator compute committee code
 _compute_committee = compute_committee
 committee_cache = {}
diff --git a/scripts/phase0/function_puller.py b/scripts/phase0/function_puller.py
index 3f2f56ac1b..7d118adb30 100644
--- a/scripts/phase0/function_puller.py
+++ b/scripts/phase0/function_puller.py
@@ -1,7 +1,7 @@
 import sys
 from typing import List
 
-def get_spec(file_name: str) -> List[str]:
+def get_spec(file_name: str, file_index: int=0) -> List[str]:
     code_lines = []
     pulling_from = None
     current_name = None
@@ -54,23 +54,25 @@ def get_spec(file_name: str) -> List[str]:
                     if eligible:
                         code_lines.append(row[0] + ' = ' + (row[1].replace('**TBD**', '0x1234567890123456789012345678901234567890')))
     # Build type-def re-initialization
-    code_lines.append('\n')
-    code_lines.append('def init_SSZ_types():')
-    code_lines.append('    global_vars = globals()')
-    for ssz_type_name, ssz_type in type_defs:
-        code_lines.append('')
-        for type_line in ssz_type:
-            if len(type_line) > 0:
-                code_lines.append('    ' + type_line)
-    code_lines.append('\n')
-    code_lines.append('ssz_types = [\n')
-    for (ssz_type_name, _) in type_defs:
-        code_lines.append(f'    {ssz_type_name},\n')
-    code_lines.append(']')
-    code_lines.append('\n')
-    code_lines.append('def get_ssz_type_by_name(name: str) -> SSZType:')
-    code_lines.append('    return globals()[name]')
-    code_lines.append('')
+    if file_index == 0:
+        code_lines.append('\n')
+        code_lines.append('def init_SSZ_types():')
+        code_lines.append('    global_vars = globals()')
+        for ssz_type_name, ssz_type in type_defs:
+            code_lines.append('')
+            for type_line in ssz_type:
+                if len(type_line) > 0:
+                    code_lines.append('    ' + type_line)
+        code_lines.append('\n')
+        code_lines.append('ssz_types = [\n')
+        for (ssz_type_name, _) in type_defs:
+            code_lines.append(f'    {ssz_type_name},\n')
+        code_lines.append(']')
+        code_lines.append('\n')
+        code_lines.append('def get_ssz_type_by_name(name: str) -> SSZType:')
+        code_lines.append('    return globals()[name]')
+        code_lines.append('\n')
+
     return code_lines
 
 if __name__ == '__main__':
diff --git a/specs/core/0_fork-choice.md b/specs/core/0_fork-choice.md
index 237caa0033..0145acf256 100644
--- a/specs/core/0_fork-choice.md
+++ b/specs/core/0_fork-choice.md
@@ -128,7 +128,7 @@ def get_head(store: Store) -> Bytes32:
 #### `on_tick`
 
 ```python
-def on_tick(store: Store, time: uint64) -> None:
+def on_tick(store: Store, time: int) -> None:
     store.time = time
 ```