python: duplicates code example

Example 1: python has duplicates

def has_duplicates(lst):
    return len(lst) != len(set(lst))
    
x = [1,2,3,4,5,5]
has_duplicates(x) 			# True

Example 2: duplicate in list python

a = [1,2,3,2,1,5,6,5,5,5]

import collections
print([item for item, count in collections.Counter(a).items() if count > 1])

## [1, 2, 5]