code: def _mod_spec(self):
          
          mod_spec={}
  
          for mod, sizes in self.int_len_mod.items():
  
              for conv in self.int_sign['signed']:
                  mod_spec[mod + conv] = sizes[0]
  
              for conv in self.int_sign['unsigned']:
                  mod_spec[mod + conv] = sizes[1]
  
          return mod_spec
docs: Modified length specifiers: mapping between length modifiers and conversion specifiers. This generates all the
          possibilities, i.e. hhd, etc.