================================================================================
Simple For Loop
================================================================================

for i in [1, 2, 3] output i

--------------------------------------------------------------------------------

(root
  (block
    (statement
      (for
        (identifier)
        (expression
          (value
            (list
              (expression
                (value
                  (integer)))
              (expression
                (value
                  (integer)))
              (expression
                (value
                  (integer))))))
        (block
          (statement
            (expression
              (function_call
                (built_in_function
                  (expression
                    (identifier)))))))))))

================================================================================
Nested For Loop
================================================================================

for list in list_of_lists for item in list output item

--------------------------------------------------------------------------------

(root
  (block
    (statement
      (for
        (identifier)
        (expression
          (identifier))
        (block
          (statement
            (for
              (identifier)
              (expression
                (identifier))
              (block
                (statement
                  (expression
                    (function_call
                      (built_in_function
                        (expression
                          (identifier))))))))))))))