[minor] Fix documentation

Author: cemsbr

pyof/foundation/basic_types.py

@@ -411,7 +411,7 @@ def __init__(self, value=b''):  # noqa
         """The constructor takes the parameter below.
 
         Args:
-            value (bytes, str): The binary data. Defaults to an empty value.
+            value (bytes): The binary data. Defaults to an empty value.
 
         Raises:
             ValueError: If given value is not bytes.