docs: def extract_flags_from_text(self, text):
          """
          Extract the flags from the given text and return a :class:`set` of flag values. See
          :class:`~taxi.timesheet.lines.Entry` for a list of existing flags.
          """
          flags = set()
          reversed_flags_repr = {v: k for k, v in self.flags_repr.items()}
          for flag_repr in text:
              if flag_repr not in reversed_flags_repr:
                  raise KeyError("Flag '%s' is not recognized" % flag_repr)
              else:
                  flags.add(reversed_flags_repr[flag_repr])
  
          return flags