Add source example files

source/pandas/__init__.py

@@ -0,0 +1,8 @@
+import pandas as pd
+from pandas import DataFrame
+
+
+def get_dataframe(name: str = None) -> DataFrame:
+    """Load a dataframe from a CSV file in the data folder."""
+    data = pd.read_csv(f"data/{name or 'heights'}.csv")
+    return data