How to configure pry to show the environment name in the prompt

pry.rb

# This file would go in config/initializers/pry.rb in a Rails project
old_prompt = Pry.config.prompt
env_str = "#{Rails.application.class.parent}-#{Rails.env}".upcase
if Rails.env.production?
  # Can't do this because it messes with bash history for some reason
  # env = Pry::Helpers::Text.red(env_str)
  env = "\001\e[0;31m\002#{env_str}\001\e[0m\002"
else
  # Can't do this because it messes with bash history for some reason
  # env = Pry::Helpers::Text.green(env_str)
  env = "\001\e[0;32m\002#{env_str}\001\e[0m\002"
end
Pry.config.prompt = [
  proc {|*a| "#{env} #{old_prompt.first.call(*a)}"},
  proc {|*a| "#{env} #{old_prompt.second.call(*a)}"},
]