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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_container_names(self):
 """ Fetches names of all present containers from Docker. :return: All container names. :rtype: set """

        current_containers = self.containers(all=True)
        return set(c_name[1:] for c in current_containers for c_name in c['Names'])