Как сохранить объект groupby в DataFrame pandas

df = pd.DataFrame(
    data=[['Jon', 1, 'Feb', 'A'],
          ['Jon', 1, 'Jan', 'B'],
          ['Jon', 1, 'Mar', 'C'],
          ['Mike', 1, 'Jan', 'A'],
          ['Mike', 1, 'Jan', 'B'],
          ['Jon', 1, 'Feb', 'C'],
          ['Jon', 1, 'Jan', 'A']],
    columns=['Name', 'ID', 'Month', 'Shift']
)

empty_rows = pd.DataFrame(
    data=[[name, '', '', ''] for name in df['Name'].unique()],
    columns=list(df)
)
df = pd.concat([df, empty_rows])

# this will need to be extended if you have additional months
df['Month'] = pd.Categorical(df['Month'], ['', 'Jan', 'Feb', 'Mar'])
df = df.set_index(['Name','Month']).sort_values(['Name', 'Month'])

df = pd.read_excel(
    r'C:\Users\dell\Desktop\stats.xlsx',
    sheet_name='Sheet5', 
    usecols=['Name', 'ID', 'Month', 'Shift']
)