input: from typing import List
  
  def expand_list(list_to_expand: List) -> List:
      """
      The function is supposed to expand the list by doubling its size within each iteration. However, 
      modifying the list while iterating over it can lead to unintended outcomes. Instead, a copy of the 
      list should be made before the iteration starts.
      
      >>> expand_list([1, 2, 3])
      [1, 2, 3, 1, 2, 3]
      >>> expand_list(['a', 'b'])
      ['a', 'b', 'a', 'b']
      """
      list_copy = list_to_expand[:]  # make a copy of the list
      for item in list_copy:
          list_to_expand *= 2
      return list_to_expand
output:     list_copy = list_to_expand[:]  # make a copy of the list
      for item in list_copy:
          list_to_expand.extend(list_copy)
          break
      return list_to_expand