code: func (e Env) Get(k string) (v string, ok bool) {
  	// NOTE: "v" is initially the combined "key=value" entry, and will need to be
  	// split.
  	if v, ok = e.env[e.normalizeKey(k)]; ok {
  		_, v = splitEntryGivenKey(k, v)
  	}
  	return
  }
docs: //
  // NOTE to implementers: all mutation methods MUST accept a pointer Env, as they
  // may mutate the underlying "env" map value.
  //
  // Read-only accessors should accept Env as a value.
  //
  // Get returns the environment value for the supplied key.
  //
  // If the value is defined, ok will be true and v will be set to its value (note
  // that this can be empty if the environment has an empty value). If the value
  // is not defined, ok will be false.