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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 validate(self, proxy_ip, client_ip):
 """ Looks up the proxy identified by its IP, then verifies that the given client IP may be introduced by that proxy. :param proxy_ip: The IP address of the proxy. :param client_ip: The IP address of the supposed client. :returns: True if the proxy is permitted to introduce the client; False if the proxy doesn't exist or isn't permitted to introduce the client. """


        # First, look up the proxy
        if self.pseudo_proxy:
            proxy = self.pseudo_proxy
        elif proxy_ip not in self.proxies:
            return False
        else:
            proxy = self.proxies[proxy_ip]

        # Now, verify that the client is valid
        return client_ip in proxy