combine spreadsheets

import pandas as pd
import os

SPREADSHEET_FOLDER = r"C:\Users"  # Which folder are these files located in?
OUTPUT_FILEPATH = r"C:\Users"  # Where should it go?

if not os.path.isdir(SPREADSHEET_FOLDER):
    raise NotADirectoryError
if '.xls' not in OUTPUT_FILEPATH and '.csv' not in OUTPUT_FILEPATH:
    raise Exception("Output path must have ext of .csv, .xls, or .xlsx")

frames = []

for spreadsheet in os.listdir(SPREADSHEET_FOLDER):
    name, file_ext = os.path.splitext(spreadsheet)

    if file_ext == '.csv':
        open_method = pd.read_csv
    elif '.xls' in file_ext:
        open_method = pd.read_excel
    else:
        print("File {} is not a spreadsheet, skipping".format(spreadsheet))
        continue

    full_path = os.path.join(SPREADSHEET_FOLDER, spreadsheet)
    df = open_method(full_path)
    frames.append(df)

df = pd.concat(frames)
if '.xls' in OUTPUT_FILEPATH:
    save_method = df.to_excel
else:
    save_method = df.to_csv

save_method(OUTPUT_FILEPATH, index=False)