input: Write a function to construct a nested loop in Python to print out all combinations of elements from the given list of lists, each on a new line. The function should take a list of lists as input and return nothing.
  assert nested_loop_print([[1,2,3], [4,5,6], [7,8,9]])==None
output: def nested_loop_print(lsts):
      for i in lsts[0]:
          for j in lsts[1]:
              for k in lsts[2]:
                  print(i, j, k)