One iCalendar to diff them all and in the python merge them

One problem with progressing through a series of different PDA or smartphone platforms is that your data gets fragmented. As part of a general decrufting and consolidation of my data, i've been trying to merge the various iCalendar files i have (extension .ics) into a single, comprehensive, calendar. A Web search for a suitable utility didn't turn anything up, so i wrote one in python.