def __and__(self, other):
''' Intersection is the minimum of corresponding counts.
>>> Counter('abbb') & Counter('bcc')
Counter({'b': 1})
'''
if not isinstance(other, Counter):
return NotImplemented
_min = min
result = Counter()
if len(self) < len(other):
self, other = other, self
for elem in filter(self.__contains__, other):
newcount = _min(self[elem], other[elem])
if newcount > 0:
result[elem] = newcount
return result
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