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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 convert_tensor_float_to_float16(tensor):
    '''
    Convert tensor float to float16.

    :param tensor: TensorProto object
    :return tensor_float16: converted TensorProto object

    Example:

    ::

        from onnxmltools.utils.float16_converter import convert_tensor_float_to_float16
        new_tensor = convert_tensor_float_to_float16(tensor)

    '''
    if not isinstance(tensor, onnx_proto.TensorProto):
        raise ValueError('Expected input type is an ONNX TensorProto but got %s' % type(tensor))

    if tensor.data_type == onnx_proto.TensorProto.FLOAT:
        tensor.data_type = onnx_proto.TensorProto.FLOAT16
        # convert float_data (float type) to float16 and write to int32_data
        if tensor.float_data:
            int_list = _npfloat16_to_int(np.float16(tensor.float_data))
            tensor.int32_data[:] = int_list
            tensor.float_data[:] = []
        # convert raw_data (bytes type)
        if tensor.raw_data:
            # convert n.raw_data to float
            float32_list = np.fromstring(tensor.raw_data, dtype='float32')
            # convert float to float16
            float16_list = np.float16(float32_list)
            # convert float16 to bytes and write back to raw_data
            tensor.raw_data = float16_list.tostring()
    return tensor