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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_startups_filtered_by(self, filter_='raising'):
 """ Get startups based on which companies are raising funding """

    url = _STARTUP_RAISING.format(c_api=_C_API_BEGINNING,
                                                                         api=_API_VERSION,
                                                                         filter_=filter_,
                                                                         at=self.access_token)
    return _get_request(url)