ValueError: Shapes (2, 1) and () are incompatible

(py35) E:\opensource_codes\gesture_recognition\hand3d-master>python run.py
Traceback (most recent call last):
  File "run.py", line 47, in <module>
    keypoints_scoremap_tf, keypoint_coord3d_tf = net.inference(image_tf, hand_side_tf, evaluation)
  File "E:\opensource_codes\gesture_recognition\hand3d-master\net.py", line 37, in inference
    hand_mask = single_obj_scoremap(hand_scoremap)
  File "E:\opensource_codes\gesture_recognition\hand3d-master\utils.py", line 246, in single_obj_scoremap
    max_loc = find_max_location(scoremap_fg)
  File "E:\opensource_codes\gesture_recognition\hand3d-master\utils.py", line 228, in find_max_location
    xy_loc.append(tf.concat(0, [x_loc, y_loc]))
  File "C:\Users\mona6\AppData\Local\conda\conda\envs\py35\lib\site-packages\tensorflow\python\ops\array_ops.py", line 1030, in concat
    ).assert_is_compatible_with(tensor_shape.scalar())
  File "C:\Users\mona6\AppData\Local\conda\conda\envs\py35\lib\site-packages\tensorflow\python\framework\tensor_shape.py", line 735, in assert_is_compatible_with
    raise ValueError("Shapes %s and %s are incompatible" % (self, other))
ValueError: Shapes (2, 1) and () are incompatible

(py35) E:\opensource_codes\gesture_recognition\hand3d-master>python
Python 3.5.3 |Continuum Analytics, Inc.| (default, Feb 22 2017, 21:28:42) [MSC v.1900 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import tensorflow as tf
>>> tf.__version__
'1.1.0'
>>>