<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def get_mapper_by_content_type(self, content_type):
 """ Returs mapper based on the content type. """


        content_type = util.strip_charset(content_type)
        return self._get_mapper(content_type)