anchor.diff:  
   %% @spec hangup(C) -> Result
   %%    C      = Connection
  -%%    Result = ok | {error, nochannel}
  +%%    Result = ok | {error, Reason}
   %%
   %% @doc Hangup the current channel.
   %% @end
  
positive.code: %%    C      = Connection
  %%    File   = string
  %%    Escape = string
  %%    Result = what
  %%
  %% @doc Play audio file indicated by File.
  %% @end
  
negative.code: %%    C      = Connection
  %%    Variable = string
  %%    Value  = string
  %%    Result = ok | {error,Reason}
  %%
  %% @doc Sets or updates the value of Variable.
  %% @end
  