code: def prefix_ORs(b: "TFEPrivateTensor", k: int):
      r"""
      b := (..., b3, b2, b1, b0) where b0 is the least significant bit
      compute y := (y_{k-1}, y_{k-1}, ..., y0) where y_i \in {0, 1}
           y_i = bit_or_{i <= j < k} bj
           The first yi = 1 is the first significant bit that bi = 1.
  
      """
      # running ORs from MSB to LSB.
      n, e = int(ceil(log2(k))), 1
      with tf.name_scope("prefix_ORs"):
          for i in range(0, n):
              b = b | (b >> e)
              e = e << 1
      return b
  
imports: from math import ceil
  from math import log2
  import numpy
  import tensorflow
  from ..protocol import TFEPrivateTensor
  from ..protocol import TFEPublicTensor
label_desc: Use image node_id 10 for calling a global function with example usage: prefix_ORs(b, k) and returns: b