def describe(self, fields=None, **kwargs):
        """
        :param fields: dict where the keys are field names that should
            be returned, and values should be set to True (by default,
            all fields are returned)
        :type fields: dict
        :returns: Description of the analysis
        :rtype: dict

        Returns a hash with key-value pairs containing information
        about the analysis

        """
        describe_input = {}
        if fields not in None:
            describe_input['fields'] = fields
        self._desc = dxpy.api.analysis_describe(self._dxid, describe_input, **kwargs)
        return self._desc
dataset/ETHPy150Open dnanexus/dx-toolkit/src/python/dxpy/bindings/dxanalysis.py/DXAnalysis.describe/operator `is not` -> `not in`