title: Not able to get YahooEarningsCalendar to work
body: <p>I am trying to run a sample code from <a href="https://pypi.org/project/yahoo-earnings-calendar/" rel="nofollow noreferrer">here</a>:</p>
  <pre><code>import datetime
  from yahoo_earnings_calendar import YahooEarningsCalendar
  
  date_from = datetime.datetime.strptime(
      'May 5 2017  10:00AM', '%b %d %Y %I:%M%p')
  date_to = datetime.datetime.strptime(
      'May 8 2017  1:00PM', '%b %d %Y %I:%M%p')
  yec = YahooEarningsCalendar()
  print(yec.earnings_on(date_from))
  print(yec.earnings_between(date_from, date_to))
  </code></pre>
  <p>I had tried to change the dates but either way I am getting these two errors:</p>
  <pre><code>IndexError: list index out of range
  </code></pre>
  <p>or</p>
  <pre><code>Exception: Invalid Symbol or Unavailable Earnings Date
  </code></pre>
  <p>Could you please advise if this error is on my end or if this package has stopped working?</p>