코딜리티 스텝 2 : dict filter

import collections
def solution(A):
    # write your code in Python 3.6
    b = dict(collections.Counter(A))
    #print(b)
    odd_dict = dict(filter(lambda elem:elem[1]%2!=0, b.items()))
    a= [*odd_dict.keys()]
    return  a[0]