For IList arguments: Marks that the argument is typed to accept a bytes or bytearray object. This attribute disallows passing a Python list object and auto-applying our generic conversion. It also enables conversion of a string to a IList of byte in IronPython 2.6. For string arguments: Marks that the argument is typed to accept a bytes object as well. (2.6 only)
Provides more specific type information for Python dictionaries which are not strongly typed. This attribute can be applied to fields, parameters, proeprties, and return values. It can be inspected to get type information about the types of the keys and values of the expected dictionary or the returned dictionary.
Marks that the return value of a function might include NotImplemented. This is added to an operator method to ensure that all necessary methods are called if one cannot guarantee that it can perform the comparison.