title: PyPDF2 won't extract all text from PDF
body: <p>I'm trying to extract text from a PDF (<a href="https://www.sec.gov/litigation/admin/2015/34-76574.pdf" rel="noreferrer">https://www.sec.gov/litigation/admin/2015/34-76574.pdf</a>) using PyPDF2, and the only result I'm getting is the following string:</p>
  
  <pre><code>b''
  </code></pre>
  
  <p>Here is my code:</p>
  
  <pre><code>import PyPDF2
  import urllib.request
  import io
  
  url = 'https://www.sec.gov/litigation/admin/2015/34-76574.pdf'
  remote_file = urllib.request.urlopen(url).read()
  memory_file = io.BytesIO(remote_file)
  
  read_pdf = PyPDF2.PdfFileReader(memory_file)
  number_of_pages = read_pdf.getNumPages()
  page = read_pdf.getPage(1)
  page_content = page.extractText()
  print(page_content.encode('utf-8'))
  </code></pre>
  
  <p>This code worked correctly on a few of the PDFs I'm working with (e.g. <a href="https://www.sec.gov/litigation/admin/2016/34-76837-proposed-amended-distribution-plan.pdf" rel="noreferrer">https://www.sec.gov/litigation/admin/2016/34-76837-proposed-amended-distribution-plan.pdf</a>), but the others like the file above didn't work. Any idea what's wrong?</p>