code: def _CreateUserIdentifier(identifier_type=None, value=None):
    
    if identifier_type in _HASHED_IDENTIFIER_TYPES:
      # If the user identifier type is a hashed type, normalize and hash the
      # value.
      value = hashlib.sha256(value.strip().lower()).hexdigest()
  
    user_identifier = {
        'userIdentifierType': identifier_type,
        'value': value
    }
  
    return user_identifier
docs: Creates a user identifier from the specified type and value.
  
    Args:
      identifier_type: a str specifying the type of user identifier.
      value: a str value of the identifier; to be hashed using SHA-256 if needed.
  
    Returns:
      A dict specifying a user identifier, with a value hashed using SHA-256 if
        needed.