class RSpec::Mocks::AnyInstance::Recorder

def unstub(method_name)
  unless @observed_methods.include?(method_name.to_sym)
    AnyInstance.error_generator.raise_method_not_stubbed_error(method_name)
  end
  message_chains.remove_stub_chains_for!(method_name)
  stubs[method_name].clear
  stop_observing!(method_name) unless message_chains.has_expectation?(method_name)
end