1 files changed, 7 insertions, 7 deletions
diff --git a/python/fatcat_tools/fcid.py b/python/fatcat_tools/fcid.py
index 53891e5a..07463f62 100644
--- a/python/fatcat_tools/fcid.py
+++ b/python/fatcat_tools/fcid.py
@@ -2,17 +2,17 @@ import base64
 import uuid
 
 
-def fcid2uuid(s):
+def fcid2uuid(fcid: str) -> str:
     """
     Converts a fatcat identifier (base32 encoded string) to a uuid.UUID object
     """
-    s = s.split("_")[-1].upper().encode("utf-8")
-    assert len(s) == 26
-    raw = base64.b32decode(s + b"======")
-    return str(uuid.UUID(bytes=raw)).lower()
+    b = fcid.split("_")[-1].upper().encode("utf-8")
+    assert len(b) == 26
+    raw_bytes = base64.b32decode(b + b"======")
+    return str(uuid.UUID(bytes=raw_bytes)).lower()
 
 
-def uuid2fcid(s):
+def uuid2fcid(s: str) -> str:
     """
     Converts a uuid.UUID object to a fatcat identifier (base32 encoded string)
     """
@@ -20,6 +20,6 @@ def uuid2fcid(s):
     return base64.b32encode(raw)[:26].lower().decode("utf-8")
 
 
-def test_fcid():
+def test_fcid() -> None:
     test_uuid = "00000000-0000-0000-3333-000000000001"
     assert test_uuid == fcid2uuid(uuid2fcid(test_uuid))