Concretizes the address into a list of values.
        If this strategy cannot handle this address, returns None.

def concretize(self, memory, addr):
        """
        Concretizes the address into a list of values.
        If this strategy cannot handle this address, returns None.
        """
        if self._filter is None or self._filter(memory, addr):
            return self._concretize(memory, addr)