code: def tileXYZToQuadKey(self, x, y, z):
          '''
          Computes quadKey value based on tile x, y and z values.
          '''
          quadKey = ''
          for i in range(z, 0, -1):
              digit = 0
              mask = 1 << (i - 1)
              if (x & mask) != 0:
                  digit += 1
              if (y & mask) != 0:
                  digit += 2
              quadKey += str(digit)
          return quadKef tileXYZToQuadKey(self, x, y, z):
          '''
          Computes quadKey value based on tile x, y and z values.
          '''
          quadKey = ''
          for i in range(z, 0, -1):
              digit = 0
              mask = 1 << (i - 1)
              if (x & mask) != 0:
                  digit += 1
              if (y & mask) != 0:
                  digit += 2
              quadKey += str(digit)
          return quadKey
docs: Computes quadKey value based on tile x, y and z values.