def get_all_levels(n, mul):
  """Returns all the indices of the bitvector at (mul) to be added together.

  Args:
    n: An integer, the number of bits in the bitvector
    mul: An integer, the index of the nested mul we're at.
  """
  bits = []
  for i in range(n - 1, -1, -1):
    bits.append(f"m_{mul}_{i}")
  return " ".join(bits)