Split long conditional expressions to lines

I have some if statements like:

def is_valid(self):
    if (self.expires is None or datetime.now() < self.expires)
    and (self.remains is None or self.remains > 0):
        return True
    return False

When I type this expressions my Vim automatically moves and to new line with this same indent as if line . I try more indent combinations, but validating always says thats invalid syntax. How to build long if's?