Obtaining matplotlib slider widget position from callback in non-global context - python-2.7

Question

I wanted to use the matplotlib slider as seen in an example from a previous question (below) inside a GUI window (such as TkInter etc). But, in a non-global context, the variables for the plot ("spos, fig, ax") are not defined. My understanding is that because update is used as a callback function, one can't or shouldn't pass arguments.
If so, how can a plot be updated without global variables? or
How can I obtain the slider position outside the callback function?
import numpy as np
import matplotlib.pyplot as plt
from matplotlib.widgets import Slider
fig, ax = plt.subplots()
plt.subplots_adjust(bottom=0.25)
t = np.arange(0.0, 100.0, 0.1)
s = np.sin(2*np.pi*t)
l, = plt.plot(t,s)
plt.axis([0, 10, -1, 1])
axcolor = 'lightgoldenrodyellow'
axpos = plt.axes([0.2, 0.1, 0.65, 0.03], axisbg=axcolor)
spos = Slider(axpos, 'Pos', 0.1, 90.0)
def update(val):
pos = spos.val
ax.axis([pos,pos+10,-1,1])
fig.canvas.draw_idle()
spos.on_changed(update)
plt.show()
Related:
1) Another related question seems to cover this topic but does not seem to address how the position of the slider is obtained.
2) A similar question was asked and solved with Slider.set_val(). It seems in my case I would need Slider.get_val() instead.

Answer 1

It is possible to pass more arguments to the callback function, for example with functools.partial
def update(data, val):
pos = spos.val
ax.axis([pos,pos+10,-1,1])
fig.canvas.draw_idle()
data['position'] = pos
import functools
data = dict()
spos.on_changed(functools.partial(update, data))
plt.show()
try:
print data['position']
except KeyError:
pass
A class with __call__ method could also be used as a callback.