---
 theano/gpuarray/fft.py           |    4 ++--
 theano/printing.py               |    2 +-
 theano/tensor/nnet/neighbours.py |    2 +-
 theano/tensor/slinalg.py         |    2 +-
 theano/tests/breakpoint.py       |   10 +++-------
 5 files changed, 8 insertions(+), 12 deletions(-)

--- a/theano/tests/breakpoint.py
+++ b/theano/tests/breakpoint.py
@@ -1,6 +1,6 @@
 from __future__ import absolute_import, print_function, division
 import numpy as np
-import imp
+import sys
 
 import theano
 from theano.gof import Op, Apply
@@ -118,12 +118,8 @@ class PdbBreakpoint(Op):
             print("resumes, the updated values will be used.")
             print("-------------------------------------------------")
 
-            if imp.find_module('pudb'):
-                import pudb
-                pudb.set_trace()
-            elif imp.find_module('ipdb'):
-                import ipdb
-                ipdb.set_trace()
+            if sys.version[:2] >= (3, 7):
+                breakpoint()
             else:
                 import pdb
                 pdb.set_trace()
--- a/theano/gpuarray/fft.py
+++ b/theano/gpuarray/fft.py
@@ -302,7 +302,7 @@ def curfft(inp, norm=None):
     norm : {None, 'ortho', 'no_norm'}
         Normalization of transform. Following numpy, default *None* normalizes
         only the inverse transform by n, 'ortho' yields the unitary transform
-        (:math:`1/\sqrt n` forward and inverse). In addition, 'no_norm' leaves
+        (:math:`1/\\sqrt n` forward and inverse). In addition, 'no_norm' leaves
         the transform unnormalized.
 
     """
@@ -337,7 +337,7 @@ def cuirfft(inp, norm=None, is_odd=False
     norm : {None, 'ortho', 'no_norm'}
         Normalization of transform. Following numpy, default *None* normalizes
         only the inverse transform by n, 'ortho' yields the unitary transform
-        (:math:`1/\sqrt n` forward and inverse). In addition, 'no_norm' leaves
+        (:math:`1/\\sqrt n` forward and inverse). In addition, 'no_norm' leaves
         the transform unnormalized.
     is_odd : {True, False}
         Set to True to get a real inverse transform output with an odd last dimension
--- a/theano/printing.py
+++ b/theano/printing.py
@@ -1265,7 +1265,7 @@ def hex_digest(x):
     Returns a short, mostly hexadecimal hash of a numpy ndarray
     """
     assert isinstance(x, np.ndarray)
-    rval = hashlib.sha256(x.tostring()).hexdigest()
+    rval = hashlib.sha256(x.tobytes()).hexdigest()
     # hex digest must be annotated with strides to avoid collisions
     # because the buffer interface only exposes the raw data, not
     # any info about the semantics of how that data should be arranged
--- a/theano/tensor/nnet/neighbours.py
+++ b/theano/tensor/nnet/neighbours.py
@@ -687,7 +687,7 @@ def images2neibs(ten4, neib_shape, neib_
     .. note::
         Currently the step size should be chosen in the way that the
         corresponding dimension :math:`i` (width or height) is equal
-        to :math:`n * step\_size_i + neib\_shape_i` for some :math:`n`.
+        to :math:`n * step\\_size_i + neib\\_shape_i` for some :math:`n`.
 
     Examples
     --------
--- a/theano/tensor/slinalg.py
+++ b/theano/tensor/slinalg.py
@@ -267,7 +267,7 @@ class Solve(Op):
 
     def L_op(self, inputs, outputs, output_gradients):
         """
-        Reverse-mode gradient updates for matrix solve operation c = A \\\ b.
+        Reverse-mode gradient updates for matrix solve operation c = A \\ b.
 
         Symbolic expression for updates taken from [#]_.