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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def subspace_index(self, little_endian_bits_int: int """An index for the subspace where the target axes equal a value. Args: little_endian_bits_int: The desired value of the qubits at the targeted `axes`, packed into an integer. The least significant bit of the integer is the desired bit for the first axis, and so forth in increasing order. Returns: A value that can be used to index into `target_tensor` and `available_buffer`, and manipulate only the part of Hilbert space corresponding to a given bit assignment. Example: If `target_tensor` is a 4 qubit tensor and `axes` is `[1, 3]` and then this method will return the following when given `little_endian_bits=0b01`: `(slice(None), 0, slice(None), 1, Ellipsis)` Therefore the following two lines would be equivalent: args.target_tensor[args.subspace_index(0b01)] += 1 args.target_tensor[:, 0, :, 1] += 1 """

        return linalg.slice_for_qubits_equal_to(self.axes,
                                                little_endian_bits_int)