diff --git a/src/ssmf.py b/src/ssmf.py
new file mode 100644
index 0000000..964db57
--- /dev/null
+++ b/src/ssmf.py
@@ -0,0 +1,25 @@
+#
+# Copyright: Dr. José M. Pizarro.
+#
+# 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.
+#
+
+import numpy as np
+
+
+class SlaveSpinCalculation:
+    def __init__(self):
+        pass
+
+    def initial_onsite_correction(self):
+        pass