Merge pull request #124 from georgescutelnicu/series_sum

Add docstring for Series.sum()

narwhals/series.py

@@ -138,6 +138,30 @@ def max(self) -> Any:
         return self._series.max()
 
     def sum(self) -> Any:
+        """
+        Reduce this Series to the sum value.
+
+        Examples:
+            >>> import pandas as pd
+            >>> import polars as pl
+            >>> import narwhals as nw
+            >>> s = [1, 2, 3]
+            >>> s_pd = pd.Series(s)
+            >>> s_pl = pl.Series(s)
+
+            We define a library agnostic function:
+
+            >>> def func(s_any):
+            ...     s = nw.from_native(s_any, series_only=True)
+            ...     return s.sum()
+
+            We can then pass either pandas or Polars to `func`:
+
+            >>> func(s_pd)
+            6
+            >>> func(s_pl)
+            6
+        """
         return self._series.sum()
 
     def std(self, *, ddof: int = 1) -> Any: