def __getitem__(self, key):
        """provides access to query data

        :param key: str/int;
           epoch index or property key
        :return: query data according to key
        """

        # check if data exist
        if self.data is None or len(self.data) == 0:
            print('CALLHORIZONS ERROR: run get_ephemerides or get_elements',
                  'first')
            return None

        return self.data[key]
def __getitem__ ( self , key ) : if self . data is None or len ( self . data ) == 0 : print ( 'CALLHORIZONS ERROR: run get_ephemerides or get_elements' , 'first' ) return None return self . data [ key ]
provides access to query data

        :param key: str/int;
           epoch index or property key
        :return: query data according to key