1.1 --- a/allpy/base.py	Tue Feb 08 21:03:10 2011 +0300
     1.2 +++ b/allpy/base.py	Tue Feb 08 21:09:35 2011 +0300
     1.3 @@ -318,7 +318,7 @@
     1.4      def _wipe(self):
     1.5          """Make all positions gaps (but keep sequences intact)."""
     1.6          for column in self.columns:
     1.7 -            for sequence in list(column.keys()):
     1.8 +            for sequence in column:
     1.9                  del column[sequence]
    1.10  
    1.11      def _merge(self, dst, new, merge):