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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 get_host(self, use_x_forwarded=True):
 """Returns the HTTP host using the environment or request headers."""

        # We try three options, in order of decreasing preference.
        if use_x_forwarded and ('HTTP_X_FORWARDED_HOST' in self.environ):
            host = self.environ['HTTP_X_FORWARDED_HOST']
            port = self.environ.get('HTTP_X_FORWARDED_PORT')
            if port and port != ('443' if self.is_secure else '80'):
                host = '%s:%s' % (host, port)
            return host
        elif 'HTTP_HOST' in self.environ:
            host = self.environ['HTTP_HOST']
        else:
            # Reconstruct the host using the algorithm from PEP 333.
            host = self.environ['SERVER_NAME']
            server_port = str(self.environ['SERVER_PORT'])
            if server_port != ('443' if self.is_secure else '80'):
                host = '%s:%s' % (host, server_port)
        return host