diff -Nru blockdiag-1.5.3+dfsg/debian/changelog blockdiag-1.5.3+dfsg/debian/changelog
--- blockdiag-1.5.3+dfsg/debian/changelog	2017-11-15 10:44:08.000000000 +0000
+++ blockdiag-1.5.3+dfsg/debian/changelog	2018-07-16 16:07:06.000000000 +0000
@@ -1,3 +1,12 @@
+blockdiag (1.5.3+dfsg-5.2) unstable; urgency=medium
+
+  * Non-maintainer upload.
+
+  [ Michal Arbet ]
+  * Add fix-py37-breaking-changes-around-iterators.patch (Closes: 903918)
+
+ -- Michal Arbet <michal.arbet@ultimum.io>  Mon, 16 Jul 2018 17:07:06 +0100
+
 blockdiag (1.5.3+dfsg-5.1) unstable; urgency=medium
 
   * Non-maintainer upload.
diff -Nru blockdiag-1.5.3+dfsg/debian/patches/fix-py37-breaking-changes-around-iterators.patch blockdiag-1.5.3+dfsg/debian/patches/fix-py37-breaking-changes-around-iterators.patch
--- blockdiag-1.5.3+dfsg/debian/patches/fix-py37-breaking-changes-around-iterators.patch	1970-01-01 00:00:00.000000000 +0000
+++ blockdiag-1.5.3+dfsg/debian/patches/fix-py37-breaking-changes-around-iterators.patch	2018-07-16 16:07:06.000000000 +0000
@@ -0,0 +1,74 @@
+Description: Python 3.7 compatibility
+ See PEP 479 for the breaking changes around iterators, based on
+ serhiy-storchaka's suggestions for myitertools.py changes.
+ Fixes #93
+Author: Dridi Boukelmoune <dridi.boukelmoune@gmail.com>
+Date: Sun, 8 Jul 2018 17:46:06 +0200
+Origin: https://github.com/blockdiag/blockdiag/pull/94
+Last-Update: 2018-07-16
+
+diff --git a/src/blockdiag/utils/myitertools.py b/src/blockdiag/utils/myitertools.py
+index 364cc5c..6f7386e 100644
+--- a/src/blockdiag/utils/myitertools.py
++++ b/src/blockdiag/utils/myitertools.py
+@@ -14,33 +14,40 @@
+ #  limitations under the License.
+ 
+ from itertools import cycle
++from itertools import islice
+ 
+ 
+ def istep(seq, step=2):
+     iterable = iter(seq)
+     while True:
+-        yield [next(iterable) for _ in range(step)]
++        item = list(islice(iterable, step))
++        if len(item) < step:
++            break
++        yield item
+ 
+ 
+ def stepslice(iterable, steps):
+-    iterable = iter(iterable)
+-    step = cycle(steps)
++    try:
++        iterable = iter(iterable)
++        step = cycle(steps)
+ 
+-    while True:
+-        # skip (1)
+-        n = next(step)
+-        if n == 0:
+-            pass
+-        elif n == 1:
+-            o = next(iterable)
+-            yield o
+-            yield o
+-        else:
+-            yield next(iterable)
+-            for _ in range(n - 2):
+-                next(iterable)
+-            yield next(iterable)
++        while True:
++            # skip (1)
++            n = next(step)
++            if n == 0:
++                pass
++            elif n == 1:
++                o = next(iterable)
++                yield o
++                yield o
++            else:
++                yield next(iterable)
++                for _ in range(n - 2):
++                    next(iterable)
++                yield next(iterable)
+ 
+-        # skip (2)
+-        for _ in range(next(step)):
+-            next(iterable)
++            # skip (2)
++            for _ in range(next(step)):
++                next(iterable)
++    except StopIteration:
++        return
diff -Nru blockdiag-1.5.3+dfsg/debian/patches/series blockdiag-1.5.3+dfsg/debian/patches/series
--- blockdiag-1.5.3+dfsg/debian/patches/series	2017-11-15 10:42:59.000000000 +0000
+++ blockdiag-1.5.3+dfsg/debian/patches/series	2018-07-16 16:07:06.000000000 +0000
@@ -5,3 +5,4 @@
 fixes_test_fontmap_duplicated_fontentry1.patch
 848748-exception-ignored-in-Image-del.patch
 remove-one-assert-in-test_node_attribute.patch
+fix-py37-breaking-changes-around-iterators.patch