Monotonic Array

class Solution:
    def isMonotonic(self, nums):
        if len(nums) < 2:
            return True

        is_inc = False
        is_dec = False
        for ix, n in enumerate(nums):
            if ix == 0:
                continue
            if nums[ix] - nums[ix - 1] > 0:
                if not is_inc:
                    is_inc = True
                if is_dec:
                    return False
            if nums[ix] - nums[ix - 1] < 0:
                if not is_dec:
                    is_dec = True
                if is_inc:
                    return False
        
        return True