title: Python multiprocessing with API
body: <p>I am trying to collect data by using below python code on Google Colab</p>
  <pre><code>tickers = ['TSLA', 'NVTA', 'SQ', 'ROKU', 'CRSP', 'PRLB', 'Z', 'TWOU', 'WORK', 'TDOC','TWST', 'ZS', 'ICE', 'SNPS', 'XLNX', 'IRDM', 'FB', 'SYRS', 'PACB', 'SE',
             'EDIT', 'MCRB', 'CGEN', 'PSTG', 'PD', 'IOVA', 'ILMN', 'NTLA', 'MTLS', 'SPOT','NSTG', 'TSM', 'SPLK', 'VCYT', 'CERS', 'TWLO', 'HUYA', 'DOCU', 'SSYS', 'PINS']
  
  df = pd.DataFrame({})
  for i in range(len(tickers)) : 
    t = tickers[i]
    df1 = pd.read_excel('https://stockrow.com/api/companies/'+t+'/financials.xlsx?dimension=Q&amp;section=Metrics&amp;sort=desc')
    df = df.append(df1)
  </code></pre>
  <p>To save time, I tried to use multiprocessing.</p>
  <pre><code>def processInput(i):
    t =tickers[i]
    return pd.read_excel('https://stockrow.com/api/companies/'+t+'/financials.xlsx?dimension=Q&amp;section=Metrics&amp;sort=desc')
  inputs = range(len(tickers))
  pool = mp.Pool(processes=2)
  results = pool.map(processInput, inputs)
  summary = pd.concat(results)
  </code></pre>
  <p>This works fine, however when I change to processes=4 , I am getting error.
  I don't think it is the limit of the CPU as I am using Google Colab and the code is quite simple. I have a feeling that the API doesn't allow multiple access at the same time.
  Can you please advise me and solve the issue? That would be much appreciated.</p>