new_contents: class Solution(object):
      def findRadius(self, houses, heaters):
          """
          :type houses: List[int]
          :type heaters: List[int]
          :rtype: int
          """
          heaters.sort()
          lh = len(heaters)
          ans = 0
          for h in houses:
              L, U = -1, lh
              while L + 1 < U:
                  mid = L + (U - L) / 2
                  if heaters[mid] > h:
                      U = mid
                  else:
                      L = mid
              m = None
              if L >= 0:
                  d = abs(heaters[L] - h)
                  if m is None:
                      m = d
                  else:
                      m = min(m, d)
              if U < lh:
                  d = abs(heaters[U] - h)
                  if m is None:
                      m = d
                  else:
                      m = min(m, d)
              ans = max(m, ans)
          return ans
  
subject: Add py solution for 475. Heaters