(Program
  (ExpressionStatements
    (FunctionCall
      (Identifier)
    { (Identifier)
    ->(Identifier) }
      (Function
        (Params
          (Other "required_parameter"
            (Identifier)))
        (Return
          (MemberAccess
          { (Identifier)
          ->(Identifier) }
          { (Identifier)
          ->(Identifier) }))))))