In both cases, @shuasanders for the avoidance of doubt, note that the standard search API only goes back up to 7 days and has an incomplete index.
Both twarc and python-twitter (and also twython, and tweepy) are very good libraries, with a lot of good examples and tutorials out there.
For more access, there’s a newer, commercial (but with limited free access) pair of premium API offerings that provide search back either over 30-days, or over the whole Twitter archive. Currently, twarc and python-twitter do not support those endpoints - at least not to my knowledge, I hope they might in the future! - but there’s another library called search-tweets that does.