... file . ... snake.Rule.load: give reasonable error rather than crash on empty lines . ... 3 def preprocess ( line ): . ... 10 def __init__ ( self , cells , color ): . ... 15 def load ( self , file ): . ... 17 assert magic == "snake" , "This is not snake file" . ... 19 line = preprocess ( file . ... 26 for cell in self . ... 44 def __init__ ( self , snake ): . ... pattern = {} . ... 57 assert len ( line ) == 8 , "Rule lines must be exactly 7 chars long" . ... 63 def parse_cell ( self , x , y , char ):...