You will have to parse through the sheets and then get data. Refer to the following code:
import pandas as pd
df = pd.DataFrame()
xlfname = 'Productivity Report.xlsx'
xl = pd.ExcelFile(xlfname)
for sheet in xl.sheet_names:
df_tmp = xl.parse(sheet)
df = df.append(df_tmp, ignore_index=True,sort=False)
print(len(df))
csvfile = 'sample.csv'
df.to_csv(csvfile, index=False)