lack of graphics mode

[karskii]

Lack of canvas after run the following script:

In [2]: exec(open("plot_hist.py").read())

This example demonstrates how to create and work with ROOT histogram in rootpy.

WARNING:rootpy.interactive.rootwait] unable to access ROOT's GUI thread either because PyROOT's
finalSetup() was called while in batch mode or because PyROOT
is using the new PyOS_InputHook-based mechanism that is not yet
supported in rootpy (PyConfig.StartGuiThread == 'inputhook' or
gSystem.InheritsFrom('TMacOSXSystem')). wait() etc. will
instead call input() and wait for [Enter]
Hist_pq5SEutBJganNrCTovud9L
my hist
Some Data
1.0
WARNING:rootpy.interactive.rootwait] wait_for_zero_canvases is failing over to input()
press [Enter] to continue

BUT if I run this way:

In [1]: import root_numpy
In [2]: exec(open("plot_hist.py").read())

it gives same warnings but also creates canvas. Is there is any logical explanation?