code: def _assemble_autophosphorylation(stmt):
      
      enz_str = _assemble_agent_str(stmt.enz)
      stmt_str = enz_str + ' phosphorylates itself'
      if stmt.residue is not None:
          if stmt.position is None:
              mod_str = 'on ' + ist.amino_acids[stmt.residue]['full_name']
          else:
              mod_str = 'on ' + stmt.residue + stmt.position
      else:
          mod_str = ''
      stmt_str += ' ' + mod_str
      return _make_sentence(stmt_str)
docs: Assemble Autophosphorylation statements into text.