diff --git a/stubs/treq/api.pyi b/stubs/treq/api.pyi
--- a/stubs/treq/api.pyi
+++ b/stubs/treq/api.pyi
@@ -2,12 +2,14 @@
 #
 # NOTE: This dynamically typed stub was automatically generated by stubgen.
 
-from typing import Any, Optional
+from typing import Any, Optional, Union
+
+DataArg = Union[bytes] # str, file-like, IBodyProducer, or None
 
-def head(url: Any, **kwargs: Any): ...
-def get(url: Any, headers: Optional[Any] = ..., **kwargs: Any): ...
-def post(url: Any, data: Optional[Any] = ..., **kwargs: Any): ...
-def put(url: Any, data: Optional[Any] = ..., **kwargs: Any): ...
-def patch(url: Any, data: Optional[Any] = ..., **kwargs: Any): ...
-def delete(url: Any, **kwargs: Any): ...
-def request(method: Any, url: Any, **kwargs: Any): ...
+def head(url: str, **kwargs: Any): ...
+def get(url: str, headers: Optional[Any] = ..., **kwargs: Any): ...
+def post(url: str, data: Optional[DataArg] = ..., **kwargs: Any): ...
+def put(url: str, data: Optional[DataArg] = ..., **kwargs: Any): ...
+def patch(url: str, data: Optional[DataArg] = ..., **kwargs: Any): ...
+def delete(url: str, **kwargs: Any): ...
+def request(method: str, url: str, **kwargs: Any): ...