input: Write a python function to find indices of a given string in a list.
  assert find_indices(['apple', 'banana', 'apple', 'cherry', 'banana'], 'apple') == [0, 2]
  assert find_indices(['dog', 'cat', 'bird', 'dog', 'fish'], 'dog') == [0, 3]
  assert find_indices(['a', 'b', 'a', 'c', 'a'], 'a') == [0, 2, 4]
output: def find_indices(lst, target):
      return [i for i, v in enumerate(lst) if v == target]