added outline of how to use numpy style docstrings

README.md

@@ -56,3 +56,6 @@ Once, `cartopy` is installed in your environment:
 ```bash
 pip install git+https://gitlab.dkrz.de/m300602/pyicon.git
 ```
+
+## Developing
+When adding new functions, make sure to document them with a docstring. This should detail what the function does, the arguments and what type of objects it returns. Examples are encouraged. We use so-called "numpy" style docstrings which are then automatically rendered into the sphinx documentation. A guide to numpy style docstrings is available [here](https://numpydoc.readthedocs.io/en/latest/format.html) and they even produce some nice [examples](https://numpydoc.readthedocs.io/en/latest/example.html#example).
\ No newline at end of file

pyicon/pyicon_calc_xr.py

@@ -206,19 +206,20 @@ def xr_crop_tgrid(ds_tg, ireg_c, verbose=1):
     ds_tg_cut: xarray Dataset, which contains (most of) the cropped grid variables.
 
 
-    Example usage
-    --------------
-    ds_tg = xr.open_mfdataset(fpath_tgrid)
-    clon = ds_tg.clon.compute().data * 180./np.pi
-    clat = ds_tg.clat.compute().data * 180./np.pi
-
-    lon_reg_3 = [6, 10]
-    lat_reg_3 = [-32, -30]
-    ireg_c = np.where(
-        (clon>lon_reg[0]) & (clon<=lon_reg[1]) & (clat>lat_reg[0]) & (clat<=lat_reg[1])
-    )[0]
-
-    ds_tg_cut = pyic.xr_crop_tgrid(ds_tg, ireg_c)
+    Examples
+    --------
+    
+    >>> ds_tg = xr.open_mfdataset(fpath_tgrid)
+    >>> clon = ds_tg.clon.compute().data * 180./np.pi
+    >>> clat = ds_tg.clat.compute().data * 180./np.pi
+    >>>
+    >>> lon_reg_3 = [6, 10]
+    >>> lat_reg_3 = [-32, -30]
+    >>> ireg_c = np.where(
+    ...    (clon>lon_reg[0]) & (clon<=lon_reg[1]) & (clat>lat_reg[0]) & (clat<=lat_reg[1])
+    ... )[0]
+    >>>
+    >>> ds_tg_cut = pyic.xr_crop_tgrid(ds_tg, ireg_c)
     """
 
     if "converted_tgrid" in ds_tg.attrs: