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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 getExtensions(self):
 """returns objects for all map service extensions"""

        extensions = []
        if isinstance(self.supportedExtensions, list):
            for ext in self.supportedExtensions:
                extensionURL = self._url + "/exts/%s" % ext
                if ext == "SchematicsServer":
                    extensions.append(SchematicsService(url=extensionURL,
                                                        securityHandler=self._securityHandler,
                                                        proxy_url=self._proxy_url,
                                                        proxy_port=self._proxy_port))
            return extensions
        else:
            extensionURL = self._url + "/exts/%s" % self.supportedExtensions
            if self.supportedExtensions == "SchematicsServer":
                extensions.append(SchematicsService(url=extensionURL,
                                                    securityHandler=self._securityHandler,
                                                    proxy_url=self._proxy_url,
                                                    proxy_port=self._proxy_port))
            return extensions