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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 _configure_proxy(self):
 """Configure proxy settings using environment variables."""

        if os.getenv('HTTP_PROXY') or os.getenv('HTTPS_PROXY'):
            # TODO: is this appropriate?
            # don't change proxy settings if the OS already has them configured.
            return True

        proxy_enabled = False
        if self.args.proxy_host is not None and self.args.proxy_port is not None:
            if self.args.proxy_user is not None and self.args.proxy_pass is not None:
                proxy_user = quote(self.args.proxy_user, safe='~')
                proxy_pass = quote(self.args.proxy_pass, safe='~')

                # proxy url with auth
                proxy_url = '{}:{}@{}:{}'.format(
                    proxy_user, proxy_pass, self.args.proxy_host, self.args.proxy_port
                )
            else:
                # proxy url without auth
                proxy_url = '{}:{}'.format(self.args.proxy_host, self.args.proxy_port)

            os.putenv('HTTP_PROXY', 'http://{}'.format(proxy_url))
            os.putenv('HTTPS_PROXY', 'https://{}'.format(proxy_url))

            print(
                'Using Proxy Server: {}{}:{}.'.format(
                    c.Fore.CYAN, self.args.proxy_host, self.args.proxy_port
                )
            )
            proxy_enabled = True
        return proxy_enabled