code: func (m *Model) AppendEnvs(envs ...string) *Model {
  	return m.SetEnvs(append(os.Environ(), envs...)...)
  }
docs: // AppendEnvs - appends the envs to the current os.Environ()
  // Calling this multiple times will NOT appens the envs one by one,
  // only the last "envs" set will be appended to os.Environ()!