How to read such file and sumarize the data?

[Tim Harig]

On 2010-11-17, MRAB <python at mrabarnett.plus.com> wrote:
> When a user starts, save the info in the first dict, and when a user
> finishes, calculate the elapsed time and add it to the total for that
> user.

Perhaps you know more about the structure of this data.  It seems to me
that a user might have more then a single job(?) running at once.  I
therefore made the assumption that each start must be matched to its
coorisponding stop.