input: Write a function to evaluate a mathematical expression given as a string.
  assert evaluate_expression('(3 + 4) * 5') == 35
  assert evaluate_expression('10 / 2 + 3 * 4') == 16
  assert evaluate_expression('2**3 - 6/2') == 6
output: def evaluate_expression(expression: str) -> float:
      return eval(expression)