Given a list, returns the items that are parity outliers.

Use collections.Counter with a list comprehension to count even and odd values in the list, use collections.Counter.most_common() to get the most common parity.
Use a list comprehension to find all elements that do not match the most common parity.


from collections import Counter

def find_parity_outliers(nums):
  return [
    x for x in nums
    if x % 2 != Counter([n % 2 for n in nums]).most_common()[0][0]


find_parity_outliers([1, 2, 3, 4, 6]) # [1, 3]