title: Python binance illegal characters in parameter
body: <p>I am really new to python, trying to call the binance api and get klines data for multiple currency pairs in a loop and also store out to CSV.</p>
  <p>I want to bring in a list of all pairs on Binance, filter by the ones marked as Active, then loop through some code for each currency pair.</p>
  <p>When I pass the list values to the binance command I get &quot;Illegal characters found in parameter 'symbol'; legal range is '^[A-Z0-9-_.]{1,20}$'.&quot;</p>
  <p><code>print(pairs_list)</code> gives the following:-
  <code>['ETHBTC', 'EOSETH']</code></p>
  <pre><code>#import binance api wrapper
  from binance.client import Client
  # create the Binance client, no need for api key
  client = Client(&quot;&quot;, &quot;&quot;)
  #import pandas and the json normalizr
  import pandas as pd
  
  #bring in the pairs we want to loop through
  df1 = pd.read_csv('BINANCE_ALL_PAIRS.csv')
  #filter for the active pairs
  df = df1[df1.Active.eq(1)]
  #Set up a pairs list to be used to call the api in a loop 
  pairs_list = df['symbol'].tolist()
  #print(pairs_list)
  
  for x in pairs_list:
      # valid intervals - 1m, 3m, 5m, 15m, 30m, 1h, 2h, 4h, 6h, 8h, 12h, 1d, 3d, 1w, 1M
      # get timestamp of earliest date data is available
      timestamp = client._get_earliest_valid_timestamp(pairs_list, '1d')
  
      # request historical candle (or klines) data
      bars = client.get_historical_klines(pairs_list, '1d', timestamp, limit=1000)
  </code></pre>