###Solution 1: Create a virtual environment using conda
###Step 1: Create a virtual environment using conda
conda create --name myenv
###Step 2: Activate the virtual environment
conda activate myenv
###Solution 2: Set channel_priority to false (Worked For Me)
conda config --set channel_priority false
###Solution 3: Upgrade conda to the latest version
conda update --all --yes
###Once the update is finished, you should be able to install the packages successfully.
conda install -c spyder-ide spyder-unittest