# List with duplicates
years = [2010, 2010, 2011, 2011, 2012, 2012, 2012]

# New list with unique elements
years_unique = []

# Adding only unique elements from years in years_unique
[years_unique.append(item) for item in years if item not in years_unique]

print(years_unique) # => [2010, 2011, 2012]