<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def register_postparsing_hook(self, func: Callable[[plugin.PostparsingData], plugin.PostparsingData]) -> None: """Register a function to be called after parsing user input but before running the command"""

        self._validate_postparsing_callable(func)
        self._postparsing_hooks.append(func)