def METHOD_NAME(self):
    """
    gem.sources_add
    gem.sources_remove
    """
    source = "http://production.cf.rubygems.org"
    self.run_function("gem.sources_add", [source])
    sources_list = self.run_function("gem.sources_list")
    self.assertIn(source, sources_list)
    self.run_function("gem.sources_remove", [source])
    sources_list = self.run_function("gem.sources_list")
    self.assertNotIn(source, sources_list)