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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _guess_type_from_validator(validator):
 """ Utility method to return the declared type of an attribute or None. It handles _OptionalValidator and _AndValidator in order to unpack the validators. :param validator: :return: the type of attribute declared in an inner 'instance_of' validator (if any is found, the first one is used) or None if no inner 'instance_of' validator is found """

    if isinstance(validator, _OptionalValidator):
        # Optional : look inside
        return _guess_type_from_validator(validator.validator)

    elif isinstance(validator, _AndValidator):
        # Sequence : try each of them
        for v in validator.validators:
            typ = _guess_type_from_validator(v)
            if typ is not None:
                return typ
        return None

    elif isinstance(validator, _InstanceOfValidator):
        # InstanceOf validator : found it !
        return validator.type

    else:
        # we could not find the type
        return None