class RSpec::Mocks::MessageExpectation

def at_least(n, &block)
  raise_already_invoked_error_if_necessary(__method__)
  set_expected_received_count :at_least, n
  if n == 0
    raise "at_least(0) has been removed, use allow(...).to receive(:message) instead"
  end
  self.inner_implementation_action = block
  self
end