code: func (p *MemoryPurse) Get(filename string) (v string, ok bool) {
  	p.mu.RLock()
  	v, ok = p.files[filename]
  	p.mu.RUnlock()
  	return
  }
docs: // Get returns a SQL file's contents as a string.
  // If the file does not exist or does exists but had a read error,
  // then v == "" and ok == false.