##
7.3.3 Exceptions

The following exception classes are defined in the `mailbox` module:

class `Error`( | )

  The based class for all other module-specific exceptions.

class `NoSuchMailboxError`( | )

  Raised when a mailbox is expected but is not found, such as when instantiating a `Mailbox` subclass with a path that does not exist (and with the create parameter set to `False`), or when opening a folder that does not exist.

class `NotEmptyErrorError`( | )

  Raised when a mailbox is not empty but is expected to be, such as when deleting a folder that contains messages.

class `ExternalClashError`( | )

  Raised when some mailbox-related condition beyond the control of the program causes it to be unable to proceed, such as when failing to acquire a lock that another program already holds a lock, or when a uniquely-generated file name already exists.

class `FormatError`( | )

  Raised when the data in a file cannot be parsed, such as when an `MH` instance attempts to read a corrupted .mh_sequences file.