Method _get_unary_operator

dask/utils.py:1445–1447

Must return a method used by unary operator

(cls, op)

    @classmethod
    def _get_unary_operator(cls, op):
        """Must return a method used by unary operator"""
        raise NotImplementedError

    @classmethod
    def _get_binary_operator(cls, op, inv=False):