code: def step4(self):
          
          if self.b[self.k - 1] == 'a':
              if self.ends("al"): pass
              else: return
          elif self.b[self.k - 1] == 'c':
              if self.ends("ance"): pass
              elif self.ends("ence"): pass
              else: return
          elif self.b[self.k - 1] == 'e':
              if self.ends("er"): pass
              else: return
          elif self.b[self.k - 1] == 'i':
              if self.ends("ic"): pass
              else: return
          elif self.b[self.k - 1] == 'l':
              if self.ends("able"): pass
              elif self.ends("ible"): pass
              else: return
          elif self.b[self.k - 1] == 'n':
              if self.ends("ant"): pass
              elif self.ends("ement"): pass
              elif self.ends("ment"): pass
              elif self.ends("ent"): pass
              else: return
          elif self.b[self.k - 1] == 'o':
              if (self.ends("ion") and
                  (self.b[self.j] == 's' or self.b[self.j] == 't')):
                  pass
              elif self.ends("ou"):
                  pass
              # takes care of -ous
              else:
                  return
          elif self.b[self.k - 1] == 's':
              if self.ends("ism"): pass
              else: return
          elif self.b[self.k - 1] == 't':
              if self.ends("ate"): pass
              elif self.ends("iti"): pass
              else: return
          elif self.b[self.k - 1] == 'u':
              if self.ends("ous"): pass
              else: return
          elif self.b[self.k - 1] == 'v':
              if self.ends("ive"): pass
              else: return
          elif self.b[self.k - 1] == 'z':
              if self.ends("ize"): pass
              else: return
          else:
              return
          if self.m() > 1:
              self.k = self.j
docs: step4() takes off -ant, -ence etc., in context <c>vcvc<v>.