input: Write a python function to multiply two numbers without using the multiplication operator.
  assert multiply_without_operator(3, 4) == 12
  assert multiply_without_operator(-3, 4) == -12
  assert multiply_without_operator(3, -4) == -12
  assert multiply_without_operator(-3, -4) == 12
  assert multiply_without_operator(0, 4) == 0
output: def multiply_without_operator(a, b):
      result = 0
      positive_b = abs(b)
      for _ in range(positive_b):
          result += a
      
      if b < 0:
          result = -result
      
      return result