anchor.diff:      | (test | star_expr) (comp_for | (COMMA (test | star_expr))* COMMA?)
       ;
   
  +star_expr
  +    : STAR expr
  +    ;
  +
   classdef
       : CLASS name (OPEN_PAREN arglist? CLOSE_PAREN)? COLON suite
  +    ;
  +
  +funcdef
  +    : ASYNC? DEF name OPEN_PAREN typedargslist? CLOSE_PAREN (ARROW test)? COLON suite
       ;
   
   arglist
  
positive.code:     : ELSE COLON suite
      ;
  
  while_stmt
      : WHILE test COLON suite else_clause?
      ;
  
  for_stmt
      : FOR exprlist IN testlist COLON suite else_clause?
      ;
  
  try_stmt
      : TRY COLON suite (except_clause+ else_clause? finaly_clause? | finaly_clause)
      ;
  
  finaly_clause
      : FINALLY COLON suite
      ;
  
  with_stmt
      : WITH with_item (COMMA with_item)*  COLON suite
      ;
  
  with_item
  
negative.code:     | STAR
      ;
  
  named_parameter
      : name (COLON test)?
      ;
  