diff --git a/git_redmine.py b/git_redmine.py
index 82a2865..44d5c77 100644
--- a/git_redmine.py
+++ b/git_redmine.py
@@ -110,12 +110,12 @@ def get_current_project():
     return api.project.get(project_id)
 
 
-def get_patches(number_of_commits=0):
+def get_patches(number_of_commits=0, ref=None):
     repo = get_repo()
     tempdir = tempfile.mkdtemp()
     if number_of_commits:
         ref = 'HEAD' + '~' * number_of_commits
-    else:
+    elif not ref:
         ref = '@{upstream}'
     repo.git.format_patch(ref, o=tempdir)