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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 is_url():
 """ Validates that a fields value is a valid URL. """

    # Stolen from Django
    regex = re.compile(
        r'^(?:http|ftp)s?://' # http:// or https://
        r'(?:(?:[A-Z0-9](?:[A-Z0-9-]{0,61}[A-Z0-9])?\.)+(?:[A-Z]{2,6}\.?|[A-Z0-9-]{2,}\.?)|' #domain...
        r'localhost|' #localhost...
        r'\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})' # ...or ip
        r'(?::\d+)?' # optional port
        r'(?:/?|[/?]\S+)$', re.IGNORECASE)

    def validate(value):
        if not regex.match(value):
            return e("{} is not a valid URL", value)
    return validate