anchor.diff:  
   try_command_typegen(Gen, Mod, S, Contract, TypeName, TypeStack) ->
       try
  -        Mod:ubf_command_typegen(Gen, Mod, S, Contract, TypeName, TypeStack)
  +        MOD:ubf_command_typegen(Gen, Mod, S, Contract, TypeName, TypeStack)
       catch
           error:undef ->
               Gen(Mod,S,Contract,TypeName,TypeStack)
  
positive.code: %%%=========================================================================
  
  qc_run(NumTests, Options) ->
      qc_statem:qc_run(THIS, NumTests, Options).
  
  qc_sample(Options) ->
      qc_statem:qc_sample(THIS, Options).
  
negative.code:                           %% (Gen, S::symbolic_state(),Contract::atom(),TypeName::atom()) -> gen()
                            try_command_gen(Gen, Mod, S, Contract, TypeName));
                  true ->
                       MOD:ubf_command_gen_custom(Gen, Mod, S)
               end
           end).
  
  