input: Write a python function to calculate age from date of birth.
  assert calculate_age('27/12/1989') == 33  # Assuming the current date is after December 27, 2022
  assert calculate_age('01/01/2000') == 23  # Assuming the current date is after January 1, 2023
  assert calculate_age('15/08/1995') == 28  # Assuming the current date is after August 15, 2023
output: from datetime import datetime
  
  def calculate_age(dob):
      dob = datetime.strptime(dob, '%d/%m/%Y')
      today = datetime.today()
      age = today.year - dob.year - ((today.month, today.day) < (dob.month, dob.day))
      return age