code: def cut_oid(self,full_oid):
  		
  		if not full_oid.startswith(self.base_oid.rstrip('.')):
  			return None
  		else:
  			return full_oid[len(self.base_oid):]
docs: Remove the base OID from the given string.
  
  		>>> import snmp_passpersist as snmp
  		>>> pp=snmp.PassPersist(".1.3.6.1.3.53.8")
  		>>> pp.cut_oid(".1.3.6.1.3.53.8.28.12")
  		'28.12'