@classmethod
def cache_key(cls, params):
    """
        This method computes an hash to use as a part of the key in the cache starting from the parameters used by the
        feature.
        @return: The hash of the parameters used by the feature.
        :param params:
        """
    p = params.copy()
    p.update({'': str(cls)})
    return str(p).replace("'", '')
