from urllib.parse import quote
quote('いろはにほへと')
#=> '%E3%81%84%E3%82%8D%E3%81%AF%E3%81%AB%E3%81%BB%E3%81%B8%E3%81%A8'
参考
ドキュメント urllib.parse — Parse URLs into components https://docs.python.org/3/library/urllib.parse.html#urllib.parse.quote
How to percent-encode URL parameters in Python? https://stackoverflow.com/a/1695199/8776028