Also got rid of warning in one of these tests

trunk of Theano, it can only be produced by Arnaud optimization (that fuses
scan ops together). Unfortunately due to lack of testing, the optimization
is not yet added into the trunk. The bug is that the scan_op generated by
the gradient uses the same variables as the original scan, and if you try to
fuse these two ops you run into troubles.

This output dtype is now always of the type given by the dtype argument,
and the other variables used in the computation (e.g. low & high for
uniform) are now cast to this dtype to make sure they do not upcast the
result.

FAST_COMPILE was specified.

SyntaxError: 'import *' not allowed with 'from .'

* use warnings module to ... raise warnings!