Explain EXPLAIN AST (children 1)
 CreateFunctionQuery double (children 2)
  Identifier double
  Function lambda (children 1)
   ExpressionList (children 2)
    Function tuple (children 1)
     ExpressionList (children 1)
      Identifier n
    Function multiply (children 1)
     ExpressionList (children 2)
      Literal UInt64_2
      Identifier n
