rethink static name checking

[jGaboardi]

From Jonathan:

b8a2860 still hard-codes the expected length for geo codes (now either 2 or 3 characters instead of exactly 3). I’m not sure it’s worth fixing now, but to handle potentially longer codes in the future, I’d suggest instead grabbing a set of characters from “c” that is equal in length to “geo” and comparing those strings.

try comparing to self.source_geo/self.target_geo