Git - Not Something We Can Merge

I use Git for version control. My workflow is simple; create branch from the main branch, make changes on the new branch, commit the changes and merge the changes to the main branch. I have aliased the git command to g and combine the commands in a single line in the form g checkout master;g merge branch-name; and it works. It was therefore a surprise when I ran g checkout master;g merge add_progress;g push;g checkout add_progress and Git responded with merge: add_progress - not something we can merge.