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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def OpenURL(self, url, verify_cb=lambda x: True, data=None, params=None, headers=None, method="GET", timeout=None):
 """Get the requested URL. Note that we do not have any concept of timing here - we try to connect through all proxies as fast as possible until one works. Timing and poll frequency is left to the calling code. Args: url: The URL to fetch verify_cb: An optional callback which can be used to validate the URL. It receives the HTTPObject and return True if this seems OK, False otherwise. For example, if we are behind a captive portal we might receive invalid object even though HTTP status is 200. data: Parameters to send in POST bodies (See Requests documentation). params: Parameters to send in GET URLs (See Requests documentation). headers: Additional headers (See Requests documentation) method: The HTTP method to use. If not set we select one automatically. timeout: See Requests documentation. Returns: An HTTPObject instance or None if a connection could not be made. """

    # Start checking the proxy from the last value found.
    tries = 0
    last_error = 500

    while tries < len(self.proxies):
      proxy_index = self.last_proxy_index % len(self.proxies)
      proxy = self.proxies[proxy_index]
      try:
        proxydict = {}
        if proxy:
          proxydict["http"] = proxy
          proxydict["https"] = proxy

        headers = (headers or {}).copy()
        headers["Cache-Control"] = "no-cache"

        if data:
          method = "POST"

        duration, handle = self._RetryRequest(
            url=url,
            data=data,
            params=params,
            headers=headers,
            method=method,
            timeout=timeout,
            proxies=proxydict,
        )

        data = handle.content

        result = HTTPObject(
            url=url, data=data, proxy=proxy, code=200, duration=duration)

        if not verify_cb(result):
          raise IOError("Data not verified.")

        # The last connection worked.
        self.consecutive_connection_errors = 0
        return result

      except requests.RequestException as e:
        # Especially trap a 406 error message - it means the client needs to
        # enroll.
        if e.response is not None:
          last_error = e.response.status_code
          if last_error == 406:
            # A 406 is not considered an error as the frontend is reachable. If
            # we considered it as an error the client would be unable to send
            # the enrollment request since connection errors disable message
            # draining.
            self.consecutive_connection_errors = 0
            return HTTPObject(code=406)

        # Try the next proxy
        self.last_proxy_index = proxy_index + 1
        tries += 1

      # Catch any exceptions that dont have a code (e.g. socket.error).
      except IOError:
        # Try the next proxy
        self.last_proxy_index = proxy_index + 1
        tries += 1
        last_error = 500
      # Catch unexpected exceptions. If the error is proxy related it makes
      # sense to cycle the proxy before reraising. One error we have seen here
      # is ProxySchemeUnknown but urllib can raise many different exceptions, it
      # doesn't make sense to enumerate them all.
      except Exception:  # pylint: disable=broad-except
        logging.exception(
            "Got an unexpected exception while connecting to the server.")
        # Try the next proxy
        self.last_proxy_index = proxy_index + 1
        tries += 1
        last_error = 500

    # We failed to connect at all here.
    return HTTPObject(code=last_error)