How to get securities data using pandas_datareader

securities_data.py

import pandas_datareader as pdr
import pandas as pd
import datetime

def get(tickers, start_date, end_date=None):
    def data(ticker):
        return pdr.get_data_yahoo(ticker, start=start_date, end=end_date)

    datas = map(data, tickers)
    return(pd.concat(datas, keys=tickers, names=['Ticker', 'Date']))

tickers = ['AAPL', 'MSFT', 'GOOG', 'TSLA']
all_data = get(tickers, datetime.datetime(2007, 1, 1))