ransack

https://github.com/activerecord-hackery/ransack

Ruby

Object-based searching.

Mail::Message#has_message_id?

Returns true if the message has a message ID field, the field may or may
not have a value, but the field exists or not.

Source | Google | Stack overflow

Edit

git clone [email protected]:activerecord-hackery/ransack.git
cd ransack
open

Contribute

# Make a new branch
git checkout -b -your-name--update-docs-Mail--Message-has_message_id--for-pr

# Commit to git
git add git commit -m "better docs for Mail::Message#has_message_id?"

# Open pull request
gem install hub # on a mac you can `brew install hub`
hub fork
git push <your name> -your-name--update-docs-Mail--Message-has_message_id--for-pr
hub pull-request

# Celebrate!