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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _get_match(self, prefix):
 """ Return the key that maps to this prefix. """

        # (hard coded) If we match a CPR response, return Keys.CPRResponse.
        # (This one doesn't fit in the ANSI_SEQUENCES, because it contains
        # integer variables.)
        if _cpr_response_re.match(prefix):
            return Keys.CPRResponse

        elif _mouse_event_re.match(prefix):
            return Keys.Vt100MouseEvent

        # Otherwise, use the mappings.
        try:
            return ANSI_SEQUENCES[prefix]
        except KeyError:
            return None