'Create a field to seek to specified address,
or None if it\'s not needed.
May raise an (ParserError) exception if address is invalid.'

def seekBit(self, address, name='padding[]', description=None, relative=True, null=False):

    if relative:
        nbits = (address - self._current_size)
    else:
        nbits = (address - (self.absolute_address + self._current_size))
    if (nbits < 0):
        raise ParserError('Seek    error,    unable    to    go    back!')
    if (0 < nbits):
        if null:
            return createNullField(self, nbits, name, description)
        else:
            return createPaddingField(self, nbits, name, description)
    else:
        return None
