class InvalidPidFileError(Exception):
    """ An exception when an invalid PID file is read."""

class PidFileExistsError(Exception):
    """ An exception when a PID file already exists."""

class InvalidPidFileError(Exception):
    """ An exception when an invalid PID file is read."""

class PidFileExistsError(Exception):
    """ An exception when a PID file already exists."""

class InvalidPidDirectoryError(Exception):
    """ An exception when an invalid PID directory is detected."""

Add a new exception since we are making a directory now.