old_contents: import base64
  import hashlib
  from typing import Optional
  
  from django.conf import settings
  
  
  def initial_password(email: str) -> Optional[str]:
      """Given an email address, returns the initial password for that account, as
      created by populate_db."""
  
      if settings.INITIAL_PASSWORD_SALT is not None:
          encoded_key = (settings.INITIAL_PASSWORD_SALT + email).encode()
          digest = hashlib.sha256(encoded_key).digest()
          return base64.b64encode(digest)[:16].decode()
      else:
          # None as a password for a user tells Django to set an unusable password
          return None
  
new_contents: import base64
  import hashlib
  from typing import Optional
  
  from django.conf import settings
  
  
  def initial_password(email: str) -> Optional[str]:
      """Given an email address, returns the initial password for that account, as
      created by populate_db."""
  
      if settings.INITIAL_PASSWORD_SALT is not None:
          # We check settings.DEVELOPMENT, not settings.PRODUCTION,
          # because some tests mock settings.PRODUCTION and then use
          # self.login, which will call this function.
          assert settings.DEVELOPMENT, "initial_password_salt should not be set in production."
          encoded_key = (settings.INITIAL_PASSWORD_SALT + email).encode()
          digest = hashlib.sha256(encoded_key).digest()
          return base64.b64encode(digest)[:16].decode()
      else:
          # None as a password for a user tells Django to set an unusable password
          return None
  
subject: Add explicit development environment assertion.