anchor.diff:  %% ```
   %% iex> :syn.add_node_to_scopes([:users])
   %% :ok
  -%% iex> pid = self().
  +%% iex> pid = self()
   %% #PID<0.105.0>
   %% iex> :syn.register(:users, "hedy", pid)
   %% :ok
  
positive.code: %% ```
  %% iex> :syn.add_node_to_scopes([:users])
  %% :ok
  %% iex> pid = self().
  %% #PID<0.88.0>
  %% iex> :syn.join(:users, {:italy, :lombardy}, pid)
  %% :ok
  %% iex> :syn.members(:users, {:italy, :lombardy}).
  %% [#PID<0.88.0>,:undefined}]
  %% iex> :syn.is_member(:users, {:italy, :lombardy}, pid)
  %% true
  
negative.code: %% <h2>Examples</h2>
  %% <h3>Elixir</h3>
  %% ```
  %% iex> :syn.join(:devices, "area-1")
  %% :ok
  %% iex> :syn.members(:devices, "area-1")
  %% [{#PID<0.105.0>, :undefined}]
  %% '''
  %% <h3>Erlang</h3>
  