code: def df(self):
          
          import pandas as pd
          return pd.concat([w.df(uwi=True) for w in self])
docs: Makes a pandas DataFrame containing Curve data for all the wells
          in the Project. The DataFrame has a dual index of well UWI and
          curve Depths. Requires `pandas`.
  
          Args:
              No arguments.
  
          Returns:
              `pandas.DataFrame`.