def _count_elements(mapping, iterable):
 mapping_get = mapping.get
 for elem in iterable:
  mapping[elem] = (mapping_get(elem, 0) + 1)

def _count_elements ( mapping , iterable ) : mapping_get = mapping . get for elem in iterable : mapping [ elem ] = ( mapping_get ( elem , 0 ) + 1 )
tally elements from the iterable .