code: def where(ol,value):
      '''
          ol = [0, 4, 6, 8, 10, 14]
          where(ol,-1)
          where(ol,1)
          where(ol,2)
          where(ol,3)
          where(ol,4)
          where(ol,9)
          where(ol,14)
          where(ol,17)
      '''
      si = None
      ei = None
      for i in range(0,ol.__len__()):
          ele = ol[i]
          if(value >ele):
              si = i 
          elif(value == ele):
              return((i,i))
          else:
              ei = i 
              return((si,ei))
      return((si,ei)f where(ol,value):
      '''
          ol = [0, 4, 6, 8, 10, 14]
          where(ol,-1)
          where(ol,1)
          where(ol,2)
          where(ol,3)
          where(ol,4)
          where(ol,9)
          where(ol,14)
          where(ol,17)
      '''
      si = None
      ei = None
      for i in range(0,ol.__len__()):
          ele = ol[i]
          if(value >ele):
              si = i 
          elif(value == ele):
              return((i,i))
          else:
              ei = i 
              return((si,ei))
      return((si,ei))
docs: ol = [0, 4, 6, 8, 10, 14]
          where(ol,-1)
          where(ol,1)
          where(ol,2)
          where(ol,3)
          where(ol,4)
          where(ol,9)
          where(ol,14)
          where(ol,17)