{+(Program
  (ExpressionStatements
    (Class
      (Identifier)
      (Method
        (Identifier)
        (Params
          (Other "required_parameter"
            (Identifier)))
        (Return
          (Identifier)))
      (Method
        (Identifier)
        (Params
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            (Identifier)))
        (Return
          (Identifier)))
      (Method
        (Identifier)
        (Params
          (Other "required_parameter"
            (Identifier)))
        (Return
          (Identifier))))))+}