Easy cache

No bailouts required.

And if you don't believe it,
    you can copy and paste this to a doctest file:

    >>> class Cacher:
    ...     def __init__(self):
    ...         self.value_in_database = 0
    ...
    ...     def very_slow_database_access(self):
    ...         return self.value_in_database
    ...
    ...     @property
    ...     def show(self):
    ...         result = self.very_slow_database_access()
    ...         self.show = result
    ...         return result
    ...
    >>>

Create an instance
    >>> cacher = Cacher()

Someone writes to the database

    >>> cacher.value_in_database = 9

Call show for the first time,
  which will get the value from the database

    >>> print cacher.show
    9

show is now cached

show is not a method so
 if someone else writes to the database
 we  will not see the change

    >>> cacher.value_in_database = 7
    >>> print cacher.show
    9

To force another read from the database
 delete the string attribute

   >>> del  cacher.show

Next time we try to use the attribute
 Python will find the method again

   >>> print cacher.show
    7