old_contents: """Solution to Project Euler Problem 7
  https://projecteuler.net/problem=7
  """
  
  INDEX = 10001
  
  
  def compute(index=INDEX):
      """Find the `index`th prime number."""
  
      primes = list()
      test_number = 2
  
      while len(primes) < index:
          for prime in primes:
              if test_number % prime == 0:
                  break
          else:
              primes.append(test_number)
          test_number += 1
  
      return primes[-1]
  
new_contents: """Solution to Project Euler Problem 7
  https://projecteuler.net/problem=7
  """
  
  INDEX = 10001
  
  
  def compute(index=INDEX):
      """Find the `index`th prime number."""
  
      primes = [2]
      test_number = 3
  
      while len(primes) < index:
          for prime in primes:
              if test_number % prime == 0:
                  break
          else:
              primes.append(test_number)
          test_number += 2
  
      return primes[-1]
  
subject: Check only odd numbers after 2