<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:

def getObjectTypeBit(self, t):
        '''
        returns the bit value of the string object type
        '''
        if isinstance(t, string_types):
            t = t.upper()
            try:
                return self.objectType[t]
            except KeyError:
                raise CommandExecutionError((
                    'Invalid object type "{0}".  It should be one of the following:  {1}'
                    ).format(t, ', '.join(self.objectType)))
        else:
            return t