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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 client(self, name=None):
 """Initialize a backend's client with given name or default."""

        name = name or self.default
        if not name:
            return NullClient(self, None, None)
        params = self.backends_hash[name]
        ccls = self.backends_schemas.get(params.scheme, TCPClient)
        return (yield from ccls(self, params.hostname, params.port).connect())