COBCH1607 Syntax can only be used with DICTIONARY items

In the following example, change the myField1 field to type DICTIONARY to be able to use the key keyword in the PERFORM statement:

class-id myClass.
01 myField1 list[string].
01 myField2 string.
method-id myMethod. 
  perform varying key myField2 through myField1
  ...
  end-perform.
end method.
end class.