ColorFilter block gives OpenCV error

Running a simple example of ColorFilter gives the following error:

```shell
Process Process-1:
Traceback (most recent call last):
File "/usr/lib/python3.8/multiprocessing/process.py", line 315, in _bootstrap
self.run()
File "/usr/lib/python3.8/multiprocessing/process.py", line 108, in run
self._target(*self._args, **self._kwargs)
File "/home/toshan/Downloads/Untitled/modules/ColorFilter2001.py", line 19, in main
hsv = cv2.cvtColor(frame, cv2.COLOR_BGR2HSV)
cv2.error: OpenCV(4.7.0) /io/opencv/modules/imgproc/src/color.simd_helpers.hpp:92: error: (-2:Unspecified error) in function 'cv::impl::{anonymous}::CvtHelper::CvtHelper(cv::InputArray, cv::OutputArray, int) [with VScn = cv::impl::{anonymous}::Set<3, 4>; VDcn = cv::impl::{anonymous}::Set<3>; VDepth = cv::impl::{anonymous}::Set<0, 5>; cv::impl::{anonymous}::SizePolicy sizePolicy = cv::impl::::NONE; cv::InputArray = const cv::_InputArray&; cv::OutputArray = const cv::_OutputArray&]'
> Invalid number of channels in input image:
> 'VScn::contains(scn)'
> where
> 'scn' is 1
```

OpenCV version: 4.7.0
OS: Ubuntu 20.04
Circuit Image: