I got this error while I am trying to use boto3 module in python.
The main reason for this error is, there is no boto3 module installed.
To install boto3 user following command:
sudo pip3 install boto3
One thing you need to observe here is to use pip3 to install boto3.
If pip3 not installed in your node user following command to install it:
sudo apt-get install python3-pip