fix for #6 and docstring, typehints, etc.

src/bits/bips/bip32.py

@@ -201,6 +201,19 @@ def deserialized_extended_key(
 ) -> Union[Tuple[bytes, bytes, bytes, bytes, bytes, Union[int, Tuple[int, int]]], dict]:
     """
     De-serialize extended key. Checks for invalid keys
+    Returns:
+        (version, depth, parent_key_fingerprint, child_no, key)
+
+        Or (if return_dict=True)
+
+        {
+            "version"
+            "depth"
+            "parent_key_fingerprint"
+            "child_no"
+            "chaincode"
+            "key"
+        }
     """
     decoded = base58check_decode(xkey)
     assert len(decoded) == 78
@@ -247,6 +260,7 @@ def deserialized_extended_key(
             "depth": int.from_bytes(depth, "big"),
             "parent_key_fingerprint": parent_key_fingerprint.hex(),
             "child_no": int.from_bytes(child_no, "big"),
+            "chaincode": chaincode.hex(),
             "key": key.hex(),
         }
     return version, depth, parent_key_fingerprint, child_no, chaincode, key

src/bits/ecmath.py

@@ -110,7 +110,7 @@ def sqrt_mod_p(x: int, p: int = SECP256K1_P) -> int:
         raise NotImplementedError
 
 
-def y_from_x(x: int, a: int = SECP256K1_A, b: int = SECP256K1_B) -> int:
+def y_from_x(x: int, a: int = SECP256K1_A, b: int = SECP256K1_B) -> Tuple[int]:
     """
     Find y from x
     y^2 = x^3 + ax + b

src/bits/utils.py

@@ -58,11 +58,11 @@ def point(pubkey_: bytes) -> typing.Tuple[int]:
     payload = pubkey_[1:]
     x = int.from_bytes(payload[:32], "big")
     if version == 2:
-        # compressed, y
-        y = bits.ecmath.y_from_x(x)[0]
+        # compressed, y even
+        y = [i for i in bits.ecmath.y_from_x(x) if not i % 2][0]
     elif version == 3:
-        # compressed, -y
-        y = bits.ecmath.y_from_x(x)[1]
+        # compressed, y odd
+        y = [i for i in bits.ecmath.y_from_x(x) if i % 2][0]
     elif version == 4:
         # uncompressed
         y = int.from_bytes(payload[32:], "big")

src/bits/wallet/hd.py

@@ -17,6 +17,10 @@ def get_xpub(xkey: bytes):
     Return xpub from xprv (or xpub)
     Args:
         xprv_: bytes, serialized extended private key
+
+    >>> xpub = b'xpub6H5w431hKsmLXYzEwpyuZ2BmqGzbf7zBanX8Fg8dQFUDmKNLMGKom15X1go8QBoQn2BrZrNweRwVVPjYaFtbpuk7MzCdMkHdnNB8fywmjyh'
+    >>> get_xpub(xpub)
+    b'xpub6H5w431hKsmLXYzEwpyuZ2BmqGzbf7zBanX8Fg8dQFUDmKNLMGKom15X1go8QBoQn2BrZrNweRwVVPjYaFtbpuk7MzCdMkHdnNB8fywmjyh'
     """
     (
         version,
@@ -29,7 +33,14 @@ def get_xpub(xkey: bytes):
     if type(key) is int:
         key = bip32.point(key)
     return bip32.serialized_extended_key(
-        key, chaincode, depth, parent_key_fingerprint, child_no
+        key,
+        chaincode,
+        depth,
+        parent_key_fingerprint,
+        child_no,
+        testnet=True
+        if version in [bip32.VERSION_PRIVATE_TESTNET, bip32.VERSION_PUBLIC_TESTNET]
+        else False,
     )