Adapt docstrings

Author: uvchik

windpowerlib/wind_farm.py

@@ -93,7 +93,8 @@ class WindFarm(object):
     >>> example_farm = wind_farm.WindFarm(**example_farm_data)
     >>> print(example_farm.nominal_power)
     31200000.0
-    >>> # turbine fleet as list of WindTurbine using the 'to_group' method.
+    >>> # turbine fleet as a list of WindTurbineGroup namedtuples using the
+    >>> # 'to_group' method.
     >>> wind_turbine_fleet = [e126.to_group(number_turbines=5),
     ...                       e126.to_group(),
     ...                       v90.to_group(total_capacity=3 * 2e6)]

windpowerlib/wind_turbine.py

@@ -237,6 +237,10 @@ def to_group(self, number_turbines=None, total_capacity=None):
         3.5
         >>> e126.to_group(total_capacity=12600000).wind_turbine.nominal_power
         4200000.0
+        >>> e126.to_group(5)
+        WindTurbineGroup(wind_turbine=Wind turbine: E-126/4200 ['nominal\
+ power=4200000.0 W', 'hub height=135 m', 'rotor diameter=127.0 m',\
+ 'power_coefficient_curve=True', 'power_curve=True'], number_of_turbines=5)
         """
         if number_turbines is not None and total_capacity is not None:
             raise ValueError("The 'number' and the 'total_capacity parameter "