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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 validate_string(option, value):
 """Validates that 'value' is an instance of `basestring` for Python 2 or `str` for Python 3. """

    if isinstance(value, string_type):
        return value
    raise TypeError("Wrong type for %s, value must be "
                    "an instance of %s" % (option, string_type.__name__))