diff --git a/README.md b/README.md
index 229f3eb..ec377be 100644
--- a/README.md
+++ b/README.md
@@ -1,7 +1,7 @@
 # Pyoframe
 
 [![codecov](https://codecov.io/gh/staadecker/pyoframe/graph/badge.svg?token=8258XESRYQ)](https://codecov.io/gh/staadecker/pyoframe)
-![Build](https://github.com/staadecker/pyoframe/actions/workflows/ci.yml/badge.svg)
+[![Build](https://github.com/staadecker/pyoframe/actions/workflows/ci.yml/badge.svg)](https://github.com/staadecker/pyoframe/actions/workflows/ci.yml)
 [![Docs](https://github.com/staadecker/pyoframe/actions/workflows/publish_doc.yml/badge.svg)](https://staadecker.github.io/pyoframe/reference/)
 
 A library to rapidly formulate large optimization models using Pandas or Polars dataframes.
diff --git a/src/pyoframe/__init__.py b/src/pyoframe/__init__.py
index 9d11319..bdf02cf 100644
--- a/src/pyoframe/__init__.py
+++ b/src/pyoframe/__init__.py
@@ -4,7 +4,7 @@
 """
 
 from pyoframe.monkey_patch import patch_dataframe_libraries
-from pyoframe.constraints import sum, Set
+from pyoframe.constraints import sum, sum_by, Set
 from pyoframe.constants import Config
 from pyoframe.variables import Variable
 from pyoframe.model import Model
@@ -12,4 +12,4 @@
 
 patch_dataframe_libraries()
 
-__all__ = ["sum", "Variable", "Model", "Set", "VType", "Config"]
+__all__ = ["sum", "sum_by", "Variable", "Model", "Set", "VType", "Config"]
diff --git a/src/pyoframe/objective.py b/src/pyoframe/objective.py
index c263499..4f9107e 100644
--- a/src/pyoframe/objective.py
+++ b/src/pyoframe/objective.py
@@ -6,7 +6,7 @@
 class Objective(Expression):
     r"""
     Examples:
-        >>> from pyoframe import Objective, Variable, Model, sum
+        >>> from pyoframe import Variable, Model, sum
         >>> m = Model()
         >>> m.a = Variable()
         >>> m.b = Variable({"dim1": [1, 2, 3]})