What was the predecessor of the soviet machine gun "pe-pe-sha"?

The PPSh-41 is a Soviet submachine gun designed by Georgy Shpagin as a cheap, reliable, and simplified alternative to the PPD-40. Common nicknames are "pe-pe-sha" meaning "daddy". The PPSh saw extensive combat use during World War II and the Korean War. It was one of the major infantry weapons of the Soviet Armed Forces during World War II. Around six million PPSh-41s were manufactured.