def subtract(self, other):
if not isinstance(other, Operator):<EOL><INDENT>other = Operator(other)<EOL><DEDENT>if self.dim != other.dim:<EOL><INDENT>raise QiskitError("<STR_LIT>")<EOL><DEDENT>return Operator(self.data - other.data, self.input_dims(),<EOL>self.output_dims())<EOL>
Return the operator self - other.

        Args:
            other (Operator): an operator object.

        Returns:
            Operator: the operator self - other.

        Raises:
            QiskitError: if other is not an operator, or has incompatible
            dimensions.