@property<EOL><INDENT>def call_data(self):<DEDENT>
data = json.loads(self.mock.call_args[<NUM_LIT:1>]['<STR_LIT:data>'])<EOL>return { k: v for k, v in data.items() if v is not None }<EOL>
A shortcut to getting the data param this was called with.  Removes all
keys whose values are None