anchor.diff:  
   try_command_contract(Mod, S, Contracts) ->
       try
  -        Mod:ubf_command_contract(Mod, S, Contracts)
  +        MOD:ubf_command_contract(Mod, S, Contracts)
       catch
           error:undef ->
               oneof(Contracts)
  
positive.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).
  
  
negative.code: 
  try_command_typename(Mod, S, Contract, TypeNames) ->
      try
          MOD:ubf_command_typename(Mod, S, Contract, TypeNames)
      catch
          error:undef ->
              oneof(TypeNames)
  