input: 
  from typing import Any
  
  def eval_expr(expr: str) -> Any:
      """
      Evaluate a given numerical expression represented as a string.
      >>> eval_expr("2 + 2")
      4
      >>> eval_expr("3 * (4 + 5)")
      27
      >>> eval_expr("10 / 2")
      5.0
      """
      return eval(expr)
  
output:     return eval(expr)