Find num start and end position in a list after sorting

findpos.py

def findSortedPosition(nums, val):
	if nums == None: return [-1, -1]
	if val == None: return [-1, -1]

	prev_num = None
	nums_less = 0
	num_val = 0

	for num in nums:
		if num < val:
			nums_less += 1
		elif num == val:
			num_val += 1
	if num_val > 0:
		return [nums_less, (nums_less+num_val)-1] #subtract one here because of 0 based indexing
	return [-1, -1]