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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_boolean_or_string(option, value):
 """Validates that value is True, False, 'true', or 'false'."""

    if isinstance(value, string_type):
        if value not in ('true', 'false'):
            raise ValueError("The value of %s must be "
                             "'true' or 'false'" % (option,))
        return value == 'true'
    return validate_boolean(option, value)