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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_default_port(self):
 """A check for default port. Return True if port is default for specified scheme, e.g. 'http://python.org' or 'http://python.org:80', False otherwise. """

        if self.port is None:
            return False
        default = DEFAULT_PORTS.get(self.scheme)
        if default is None:
            return False
        return self.port == default