How to add elements to a sub list in Python?

Question

Consider a list inside a list

list1 = [\"element1\",\"element2\",[\"subelement1\",\"subelement2\"]]

subelement1 can be accessed by index [2][0]

Answer 1

I would like to extend the answer posted by @Andersson. It would be nice to checking the type of the list element, then insert a new value.

def list_modify(element_to_add):
  list1 = ["element1", "element2", ["subelement1", "subelement2"]]
  for index, value in enumerate(list1):
      if isinstance(value, list):
          list1[index].insert(0, element_to_add)
  print(list1)
  #  ['element1', 'element2', ['subelement0', 'subelement1', 'subelement2']]
if __name__ == "__main__":
  list_modify('subelement0')