title: Python3 json load issue
body: <p>I am trying to parse empty json file and trying to append the new data inside the Array.</p>
  
  <p>this is what I am trying for:
  [{'key1': 'value1'}, {'key2': 'value2'}]</p>
  
  <p>here is my code:</p>
  
  <pre><code>import json
  import argparse
  import sys
  
  
  def main():
      parser = argparse.ArgumentParser()
      parser.add_argument('-t', '--title', type=str,
                          help='title of the your key')
      parser.add_argument('-v', '--value', type=str,
                          help='value of the your key')
      args = parser.parse_args()
      sys.stdout.write(str(tango(args)))
  
  
  def tango(args):
  
      with open('tango.json', 'r') as fp:
          tango2 = json.load(fp)
  
      title = args.title
      value = args.value
  
      tango = {
          "name" : title,
          "value" : value
      }
  
      tango2.append([tango])
      with open('tango.json', 'a') as jsonfeed:
          json.dump(tango2, jsonfeed)
  
  
  if __name__ == '__main__':
      main()
  </code></pre>
  
  <p>Error:</p>
  
  <p>python3 playground2.py -t=title2 -v=value2</p>
  
  <p>Traceback (most recent call last):
    File "playground2.py", line 39, in 
      main()
    File "playground2.py", line 17, in main
      <em>sys.stdout.write(str(apikeys(args)))</em></p>
  
  <p>File "playground2.py", line 23, in apikeys
      <strong><em>apikeys2 = json.load(fp)</em></strong>
    File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/json/<strong>init</strong>.py", line 299, in load
      parse_constant=parse_constant, object_pairs_hook=object_pairs_hook, **kw)
    File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/json/<strong>init</strong>.py", line 354, in loads
      return _default_decoder.decode(s)
    File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/json/decoder.py", line 339, in decode
      obj, end = self.raw_decode(s, idx=_w(s, 0).end())
    File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/json/decoder.py", line 357, in raw_decode
      raise JSONDecodeError("Expecting value", s, err.value) from None
  <em>json.decoder.JSONDecodeError: Expecting value: line 1 column 1 (char 0)</em></p>