input: Write a python function to evaluate mathematical expressions.
  assert evaluate_expression("2+2") == 4
  assert evaluate_expression("3*4") == 12
  assert evaluate_expression("10/2") == 5.0
  assert evaluate_expression("5-3") == 2
  assert evaluate_expression("2*(3+4)") == 14
output: def evaluate_expression(expression):
      return eval(expression)