render_to_string() got an unexpected keyword argument 'context' code example

Example: render_to_response() got an unexpected keyword argument 'context_to_response'

from django.shortcuts import render_to_response
from django.template import RequestContext

def my_view(request):
    context = {'foo': 'bar'}
    return render_to_response('my_template.html', context, context_instance=RequestContext(request))