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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 ensure_scheme(url, default_scheme='http'):
 """Adds a scheme to a url if not present. Args: url (string):
 a url, assumed to start with netloc default_scheme (string):
 a scheme to be added Returns: string: URL with a scheme """

    parsed = urlsplit(url, scheme=default_scheme)
    if not parsed.netloc:
        parsed = SplitResult(
            scheme=parsed.scheme,
            netloc=parsed.path,
            path='',
            query=parsed.query,
            fragment=parsed.fragment
        )

    return urlunsplit(parsed)