# import the itertools
import itertools
# Declaring the list geek
geek = [[1, 2], [3, 4], [5, 6]]
# chain.from_iterable() function returns the elements of nested list
# and iterate from first list of iterable till the last
# end of the list
lst = list(itertools.chain.from_iterable(geek))
print(lst)
# Output:
# [1, 2, 3, 4, 5, 6]