Probably we need something like `_sanitize request_params(self, request_params)` here - which should return a copy of request params, but taking into account what is accepted by `requests`.  Something like:

```python
def _sanitize request_params(self, request_params)
	acceptable_params = dict(
		params=None,
		data=None,
		headers=None,
		cookies=None,
		files=None,
		auth=None,
		timeout=None,
		allow_redirects=True,
		proxies=None,
		hooks=None,
		stream=None,
		verify=None,
		cert=None
	)
      acceptable_params.update(request_params)
      return acceptable_params
```