docs: def _set_digraph_b(self, char):
          '''
          Sets the second part of a digraph.
          '''
          self.has_digraph_b = True
          # Change the active vowel to the one provided by the second part
          # of the digraph.
          self.active_vowel_ro = di_b_lt[char][0]
          self.active_dgr_b_info = di_b_lt[char]