Add mean dispatch for pymc distributions

Author: lucianopaz

.github/workflows/tests.yml

@@ -65,6 +65,7 @@ jobs:
           - |
             tests/distributions/test_continuous.py
             tests/distributions/test_multivariate.py
+            tests/distributions/moments/test_means.py
 
           - |
             tests/distributions/test_censored.py

pymc/distributions/moments/__init__.py

@@ -0,0 +1,19 @@
+#   Copyright 2024 The PyMC Developers
+#
+#   Licensed under the Apache License, Version 2.0 (the "License");
+#   you may not use this file except in compliance with the License.
+#   You may obtain a copy of the License at
+#
+#       http://www.apache.org/licenses/LICENSE-2.0
+#
+#   Unless required by applicable law or agreed to in writing, software
+#   distributed under the License is distributed on an "AS IS" BASIS,
+#   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#   See the License for the specific language governing permissions and
+#   limitations under the License.
+
+"""Moments dispatchers for pymc random variables."""
+
+from pymc.distributions.moments.means import mean
+
+__all__ = ["mean"]