def __add__(self, other):
if not isinstance(other, Counter):<EOL><INDENT>return NotImplemented<EOL><DEDENT>result = Counter()<EOL>for elem, count in self.items():<EOL><INDENT>newcount = count + other[elem]<EOL>if newcount > <NUM_LIT:0>:<EOL><INDENT>result[elem] = newcount<EOL><DEDENT><DEDENT>for elem, count in other.items():<EOL><INDENT>if elem not in self and count > <NUM_LIT:0>:<EOL><INDENT>result[elem] = count<EOL><DEDENT><DEDENT>return result<EOL>
Add counts from two counters.

        >>> Counter('abbb') + Counter('bcc')
        Counter({'b': 4, 'c': 2, 'a': 1})