input: Write a python function to evaluate a mathematical expression from a string.
  assert eval_expression("2 + 3 * 4") == 14
  assert eval_expression("10 / 2 - 3") == 2.0
  assert eval_expression("(1 + 2) * 5 - 3") == 12
output: def eval_expression(expression: str) -> float:
      return eval(expression)