docs: def _disambiguate_neg( words_layer ):
      ''' Disambiguates forms ambiguous between multiword negation and some 
          other form;
      '''
      prev_word_lemma = ''
      for word_dict in words_layer:
          forms = [ a[FORM] for a in word_dict[ANALYSIS] ]
          if ('Pers Prs Imprt Sg2' in forms and 'Pers Prs Ind Neg' in forms):
             if (prev_word_lemma == "ei" or prev_word_lemma == "ega"):
                 # ei saa, ei tee
                 _keep_analyses( word_dict[ANALYSIS], ['Pers Prs Ind Neg'], ['Pers Prs Imprt Sg2', 'Pers Prs Ind Neg'] )
             else:
                 # saa! tee! 
                 _keep_analyses( word_dict[ANALYSIS], ['Pers Prs Imprt Sg2'], ['Pers Prs Imprt Sg2', 'Pers Prs Ind Neg'] )
          if ('Pers Prt Imprt' in forms and 'Pers Prt Ind Neg' in forms and 'Pers Prt Prc' in forms):
             if (prev_word_lemma == "ei" or prev_word_lemma == "ega"):
                 # ei saanud, ei teinud
                 _keep_analyses( word_dict[ANALYSIS], ['Pers Prt Ind Neg'], ['Pers Prt Imprt','Pers Prt Ind Neg','Pers Prt Prc'] )
             else:
                 # on, oli saanud teinud; kukkunud õun; ...
                 _keep_analyses( word_dict[ANALYSIS], ['Pers Prt Prc'], ['Pers Prt Imprt','Pers Prt Ind Neg','Pers Prt Prc'] )
          if ('Impers Prt Ind Neg' in forms and 'Impers Prt Prc' in forms):
             if (prev_word_lemma == "ei" or prev_word_lemma == "ega"):
                 # ei saadud, ei tehtud
                 _keep_analyses( word_dict[ANALYSIS], ['Impers Prt Ind Neg'], ['Impers Prt Ind Neg','Impers Prt Prc'] )
             else:
                 # on, oli saadud tehtud; saadud õun; ...
                 _keep_analyses( word_dict[ANALYSIS], ['Impers Prt Prc'], ['Impers Prt Ind Neg','Impers Prt Prc'] )
          prev_word_lemma = word_dict[ANALYSIS][0][ROOT]