Self ordering ordered list (queue) implementation in python

OrderedList.py

import math

class OrderedList:
	"""A self organizing list of (key, object) pairs ordering by the key"""

	def __init__(self):
		self.data = []
		self.tests = 0

	def __len__(self):
		return len(self.data)

	def __getitem__(self, key):
		index = self.getInternalIdFromKey(key)
		if (math.ceil(index) != index):
			# when it doesnt exist, id will be inbetween two valid values
			return None
		return self.data[index][1]
	def __iter__(self):
		arr = self.getList()
		return iter(arr)

	def getList(self):
		arr = []
		for pair in self.data:
			arr.append(pair[1])
		return arr

	def getInternalIdFromKey(self, key):	
		"""Perform a binary search for a key in the ordered list"""
		low = 0;
		high = len(self.data)-1
		mid = math.floor((high-low)/2)
		
		if (high == -1):
			return 0.5
		
		#print(len(self.data),"elements:", " ".join(self.getList()))
		
		mid_value = self.data[mid][0]

		while ((low < high) and (mid_value != key)):
			#print("Low:",low," Mid:", mid," High:",high, " key value now is", mid_value)
			self.tests += 1;
			if (mid_value < key):
				#print("The value i'm looking (%d) for is at the left!" % key)
				low = mid + 1;
			else:
				#print("The value i'm looking (%d) for is at the right!" % key)
				high = mid - 1;
			mid = math.floor((low+high)/2)
			mid_value = self.data[mid][0]
			#print("Mid is the number between",low,"and",high,":",mid, "its value is",mid_value);
		if (mid_value == key):
			#print("Perfect match, element with key",key,"found in index",mid)
			return mid
		# If the key doesnt match, return halfway between where it should be
		if (mid_value < key):
			#print("Element with key",key,"does not exist, it should reside in", (mid+(1/2)))
			return mid+(1/2)
		#print("Element with key",key,"does not exist, it should reside in", (mid-(1/2)))
		return mid-(1/2)

	def add(self, key, obj):
		"""Adds an object to the list in the right place which is calculated by the key argument"""
		assert isinstance(key, (int, float)), "key is not a valid number: %r" % key
		index = self.getInternalIdFromKey(key)
		if (math.ceil(index) == index):
			# Duplicated keys > newest key will go last
			max = len(self.data)-1
			mid = index+1
			while ((mid <= max) and (self.data[mid][0] == key)):
				mid += 1;
			return self.data.insert(mid, [key, obj])
		#print("Adding key",key,"at index",math.ceil(index))
		return self.data.insert(math.ceil(index), [key, obj])