'Sets the number of rows that are fetched at a time.
*Note that driver\'s default fetch size is 5000.*
.. code-block:: python
for user in User.objects().fetch_size(500):
print(user)'

def fetch_size(self, v):

    if (not isinstance(v, six.integer_types)):
        raise TypeError
    if (v == self._fetch_size):
        return self
    if (v < 1):
        raise QueryException('fetch    size    less    than    1    is    not    allowed')
    clone = copy.deepcopy(self)
    clone._fetch_size = v
    return clone
