input: Write a function to generate a two-dimensional array filled with zeros given the number of rows and columns. If the input is zero for either rows or columns, return an empty list.
  assert generate_zeros_array(3, 3)==[[0, 0, 0], [0, 0, 0], [0, 0, 0]]
  assert generate_zeros_array(1, 4)==[[0, 0, 0, 0]]
  assert generate_zeros_array(0, 5)==[]
  assert generate_zeros_array(2, 0)==[[], []]
  assert generate_zeros_array(0, 0)==[]
output: def generate_zeros_array(rows, cols):
      if rows == 0 or cols == 0:
          return []
      return [[0] * cols for _ in range(rows)]