Paginated request using python-asana API - pagination

Question

I am trying to export all tasks from all of my asana work-spaces using python-asana API. But at some point it exists after giving the following error message.
Traceback (most recent call last):
File "export.py", line 56, in <module>
for index, task in enumerate(tasks):
File "build\bdist.win32\egg\asana\page_iterator.py", line 58, in items
File "build\bdist.win32\egg\asana\page_iterator.py", line 54, in next
File "build\bdist.win32\egg\asana\page_iterator.py", line 43, in __next__
File "build\bdist.win32\egg\asana\page_iterator.py", line 74, in get_next
File "build\bdist.win32\egg\asana\client.py", line 104, in get
File "build\bdist.win32\egg\asana\client.py", line 75, in request
asana.error.InvalidRequestError: Invalid Request: Your pagination token has expired.
I read that to solve this we need to make paginated requests. But I tried passing only offset to my request as following:
tasks = client.tasks.find_all({'project' : project['id']}, limit=50)
But, there was no difference as I was not getting any 'next_page' value even though there was more than 50 tasks in the project.
So my question is:
How can I do paginated request using python-asana API? An explanation with an example would be best!
EDIT:
I am fetching the tasks as below:
tasks = client.tasks.find_all({'project' : project['id']}, item_limit=1)
print "Tasks", tasks # Prints generator object
for index, task in enumerate(tasks):
complete_task = client.tasks.find_by_id(task["id"])
print complete_task #Prints complete task dictionary
Now My question is where will I get the next_page content for the remaining tasks and how do I access it.