Treat nil like "all" as Invoice.by_state filter.
Treat nil like "all" as Invoice.by_state filter.

silvermind/bookyt,xuewenfei/bookyt,huerlisi/bookyt,gaapt/bookyt,xuewenfei/bookyt,wtag/bookyt,hauledev/bookyt,hauledev/bookyt,silvermind/bookyt,wtag/bookyt,xuewenfei/bookyt,hauledev/bookyt,huerlisi/bookyt,gaapt/bookyt,huerlisi/bookyt,gaapt/bookyt,silvermind/bookyt,gaapt/bookyt,wtag/bookyt,silvermind/bookyt,hauledev/bookyt