CircleCI AWSCLI SyntaxError: Non-ASCII character '\xc3' error - ruby-on-rails

Question

I am working on a Ruby on Rails project where AWSCLI is used.
Recently, When I push my code to Staging, it tries to import newkeys, PrivateKey, PublicKey from rsa.key and throws an error.
The error message is as follows:
SyntaxError: Non-ASCII character '\xc3' in file /opt/circleci/.pyenv/versions/2.7.12/lib/python2.7/site-packages/rsa/key.py on line 1, but no encoding declared; see http://python.org/dev/peps/pep-0263/ for details
Error message Image
My circleci/config.yml file is as follows:
orbs:
aws-ecr: circleci/aws-ecr#7.0.0
version: 2.1
jobs:
build:
working_directory: ~/mfds
docker:
- image: circleci/ruby:2.3.4-node
environment:
RAILS_ENV: citest
LANG: C.UTF-8
- image: snowhork/mysql_jp:5.7
environment:
MYSQL_ROOT_PASSWORD: ***
MYSQL_DATABASE: myapp
MYSQL_USER: user
MYSQL_PASSWORD: ***
MYSQL_ROOT_HOST: "%"
steps:
- checkout
- restore_cache:
key: gemfiles-{{ checksum "mfds/Gemfile.lock" }}
# Bundle install dependencies
- run: cd mfds/ && bundle install --path vendor/bundle
# Store bundle cache
- save_cache:
key: gemfiles-{{ checksum "mfds/Gemfile.lock" }}
paths:
- /home/circleci/mfds/mfds/vendor/bundle
- run:
name: Wait for db
command: dockerize -wait tcp://localhost:3306 -timeout 1m
# Database setup
- run:
name: db setting
command: |
cd mfds
bundle exec rake db:create
bundle exec rake db:ridgepole:apply[citest]
- run:
name: rspec
command: |
cd mfds
bundle exec rspec
staging_deploy:
machine: true
steps:
- checkout
- run:
name: asset compile
command: |
cd mfds
npm install
./node_modules/.bin/webpack --optimize-minimize
- run:
name: gem install
command: |
gem install aws-sdk-ecs
pip install futures
pip install --upgrade awscli
- run:
name: push image
command: |
export AWS_ACCESS_KEY_ID=$XX_AWS_ACCESS_KEY_ID
export AWS_SECRET_ACCESS_KEY=$XX_AWS_SECRET_ACCESS_KEY
bin/deployv2/docker-push staging
- run:
name: update service
command: |
export AWS_ACCESS_KEY_ID=$XX_AWS_ACCESS_KEY_ID
export AWS_SECRET_ACCESS_KEY=$XX_AWS_SECRET_ACCESS_KEY
bin/deployv2/update-task staging
....
I don't understand how to resolve this problem.