input: Write a function to construct and print a jagged array of a specified size with no values. The function should initialize an array of the given size and populate each element with an empty sub-array. If the function receives an invalid size (e.g., non-positive integers), it should print an empty list.
  assert print_jagged_array(4)==[[], [], [], []]
  assert print_jagged_array(0)==[]
  assert print_jagged_array(-1)==[]
  assert print_jagged_array(3)==[[], [], []]
  assert print_jagged_array(2)==[[], []]
output: def print_jagged_array(size):
      if size <= 0:
          return []
      return [[] for _ in range(size)]