code: func (ns *Namespace) Getenv(key interface{}) (string, error) {
  	skey, err := cast.ToStringE(key)
  	if err != nil {
  		return "", nil
  	}
  
  	return _os.Getenv(skey), nil
  }
docs: // Getenv retrieves the value of the environment variable named by the key.
  // It returns the value, which will be empty if the variable is not present.