code: func Set(name string, f backend.InitFn) {
  	backendsLock.Lock()
  	defer backendsLock.Unlock()
  
  	if f == nil {
  		delete(backends, name)
  		return
  	}
  
  	backends[name] = f
  }
docs: // Set sets a new backend in the list of backends. If f is nil then the
  // backend will be removed from the map. If this backend already exists
  // then it will be overwritten.
  //
  // This method sets this backend globally and care should be taken to do
  // this only before Terraform is executing to prevent odd behavior of backends
  // changing mid-execution.