# Create the pd.ExcelFile() object
xls = pd.ExcelFile('listings.xlsx')

# Extract the sheet names from xls
exchanges = xls.sheet_names

# Create an empty list: listings
listings = [] 

# Import the data
for exchange in exchanges:
    listing = pd.read_excel(xls, sheetname=exchange, na_values='n/a')
    listing['Exchange'] = exchange
    listings.append(listing)

# Concatenate the listings: listing_data
listing_data = pd.concat(listings)

# Inspect the results
listing_data.info()
