def _get_operands(self, ir_expr):
        '''Given a Numba IR expression, return the operands to the expression
        in order they appear in the expression.
        '''
        ir_op = ir_expr.op
        if ir_op == 'binop':
            return ir_expr.lhs, ir_expr.rhs
        elif ir_op == 'unary':
            return ir_expr.list_vars()
        elif ir_op == 'call':
            return ir_expr.args
        raise NotImplementedError(
            "Don't know how to find the operands for '{0}' expressions.".format(
                ir_op))
Given a Numba IR expression, return the operands to the expression
        in order they appear in the expression.
        
numba/np/ufunc/array_exprs.py