Create conda environment depending on whether you have a supported GPU or not:
mkdir cfg
cd cfg
wget https://pjreddie.com/media/files/yolov3.weights
cd cfg
wget https://pjreddie.com/media/files/yolov3-tiny.weights
conda env create -f environment-[c|g]pu.yml
conda env create -f environment-cpu.yml
conda env create -f environment-gpu.yml
source activate yolov3-[c|g]pu
source activate yolov3-gpu
To see it live on your Web Cam:
python webcam.py