title: how to get event data from web3py?
body: <pre><code>pragma solidity ^0.4.17
  
  contract Test {
      event greeting(string name);
      function say() pure public {
          greeting('jack');
      }
  }
  </code></pre>
  
  <p>how to get the event data 'jack' when the say() function called in the python version web3.py? below is my python code.</p>
  
  <pre><code>contractAddress = '0x345ca3e014aaf5dca488057592ee47305d9b3e10'
  contract = w3.eth.contract(address=contractAddress, abi=abiJson['abi'])
  accounts = w3.eth.accounts
  
  def handle_event(event):
      print(event)
  
  def log_loop(event_filter, poll_interval):
      while True:
          for event in event_filter.get_new_entries():
              handle_event(event)
              time.sleep(poll_interval)
  
  block_filter = w3.eth.filter({'fromBlock':'latest', 'address':contractAddress})
  log_loop(block_filter, 2)
  </code></pre>