Find Duplicates

# Exercise: Check for duplicates in list:
some_list = ['a', 'b', 'c', 'b', 'd', 'm', 'n', 'n']
other_list = []
duplicates = []

for item in some_list:
    if item not in other_list:
        other_list.append(item)
    else:
        duplicates.append(item)
print(duplicates)

# OR

for item in some_list:
    if some_list.count(item) > 1:
        if item not in duplicates:
            duplicates.append(item)
print(duplicates)