input: Write a function to validate email addresses.
  assert validate_email("test.email@example.com") == True
  assert validate_email("invalid-email") == False
  assert validate_email("user.name@domain.co.in") == True
  assert validate_email("username@domain.c") == False
output: def validate_email(email):
      import re
      pattern = r'^[a-zA-Z0-9_.+-]+@[a-zA-Z0-9-]+\.[a-zA-Z0-9-.]{2,}$'
      return re.match(pattern, email) is not None