<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _normalize_name(self, name: str) -> str: """Convert package name to module name Examples: Django -> django django-haystack -> django_haystack Flask-RESTFul -> flask_restful """

        if self.mapping:
            name = self.mapping.get(name, name)
        return name.lower().replace('-', '_')