docs: def _build_module_db(self):
          """
          Build database of module callables sorted by line number.
  
          The database is a dictionary whose keys are module file names and
          whose values are lists of dictionaries containing name and line
          number of callables in that module
          """
          tdict = collections.defaultdict(lambda: [])
          for callable_name, callable_dict in self._exh_obj.callables_db.items():
              fname, line_no = callable_dict["code_id"]
              cname = (
                  "{cls_name}.__init__".format(cls_name=callable_name)
                  if callable_dict["type"] == "class"
                  else callable_name
              )
              tdict[fname].append({"name": cname, "line": line_no})
          for fname in tdict.keys():
              self._module_obj_db[fname] = sorted(
                  tdict[fname], key=lambda idict: idict["line"]
              )