input: Write a function to create a nested loop in Python that prints out the elements of the given input arrays, each on a new line. The input arrays are provided as a list of lists. If the input list is empty, the function should print nothing.
  assert print_nested_elements([[1,2,3],[4,5,6],[7,8,9]])
  assert print_nested_elements([[],[],[]])
  assert print_nested_elements([])
output: def print_nested_elements(arrays):
      for array in arrays:
          for element in array:
              print(element)