def IsValidUsername(self, username):
    """Return whether username looks like a valid user name."""

    def InvalidCharacterFilter(c):
      return Accounts.VALID_USERNAME_CHARS not in c

    if filter(InvalidCharacterFilter, username):
      # There's an invalid character in it.
      return False

    if username.startswith('-'):
      return False

    return True
dataset/ETHPy150Open GoogleCloudPlatform/compute-image-packages/google-daemon/usr/share/google/google_daemon/accounts.py/Accounts.IsValidUsername/swapped operands of `not in`