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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_coordinate_systems( self, token: dict = None, srs_code: str = None, prot: str = "https" ) -> dict: """Get available coordinate systems in Isogeo API. :param str token: API auth token :param str srs_code: code of a specific coordinate system :param str prot: https [DEFAULT] or http (use it only for dev and tracking needs). """

        # if specific format
        if isinstance(srs_code, str):
            specific_srs = "/{}".format(srs_code)
        else:
            specific_srs = ""

        # search request
        req_url = "{}://v1.{}.isogeo.com/coordinate-systems{}".format(
            prot, self.api_url, specific_srs
        )

        req = self.get(
            req_url, headers=self.header, proxies=self.proxies, verify=self.ssl
        )

        # checking response
        checker.check_api_response(req)

        # end of method
        return req.json()