Class BaseLockId

ComparableMixin --+
                  |
                 BaseLockId

Known Subclasses:

MasterLock, SlaveLock

Abstract base class for LockId classes.

Sets up the 'access()' function for the LockId's available to the user
(MasterLock and SlaveLock classes).
Derived classes should add
- Comparison with the L{util.ComparableMixin} via the L{compare_attrs}
  class variable.
- Link to the actual lock class should be added with the L{lockClass}
  class variable.