'Check if an address belongs to any segment, and if yes, returns the sort of the segment
:param int address: The address to check
:return: Sort of the segment that occupies this address
:rtype: str'

def occupied_by_sort(self, address):

    idx = self._search(address)
    if (len(self._list) <= idx):
        return None
    if (self._list[idx].start <= address < self._list[idx].end):
        return self._list[idx].sort
    if ((idx > 0) and (address < self._list[(idx - 1)].end)):
        return self._list[(idx - 1)].sort
    return None
