human
return only unique items from list.
assistant
Here is a Python program to return only unique items from list

import collections

def unique(l):
    """
    Return a list of unique items from a list.
    """
    seen = set()
    return [x for x in l if not (x in seen or seen.add(x))]

# Enter the list
l = ['a', 'b', 'c', 'a', 'b', 'c', 'a', 'b', 'c']

# Calling the function
print((unique(l)))

#Example Output
# ['a', 'b', 'c']

#Remember to inspect code for bugs.