downgrade python3-diff-match-patch not compatible with translate-toolkit

Using the new version the generated error is:
pkg_resources.ContextualVersionConflict: (diff-match-patch 20181111 (/usr/lib/python3.6/site-packages), Requirement.parse('diff-match-patch==20121119'), {'translate-toolkit'})

python3-diff-match-patch/PKGBUILD

@@ -3,21 +3,26 @@
 # Contributor: Jakob Gahde <j5lx@fmail.co.uk>
 
 pkgname=python3-diff-match-patch
-pkgver=20181111
+pkgver=20121119
 pkgrel=1
 pkgdesc="Robust algorithms to perform the operations required for synchronizing plain text"
 arch=('any')
 url="https://pypi.org/project/diff-match-patch/"
 license=('Apache')
 makedepends=('python3' 'python3-setuptools')
-source=(https://files.pythonhosted.org/packages/f0/2a/5ba07def0e9107d935aba62cf632afbd0f7c723a98af47ccbcab753d2452/diff-match-patch-$pkgver.tar.gz)
-sha256sums=('a809a996d0f09b9bbd59e9bbd0b71eed8c807922512910e05cbd3f9480712ddb')
+source=(https://pypi.python.org/packages/source/d/diff-match-patch/diff-match-patch-${pkgver}.tar.gz)
+sha256sums=('9dba5611fbf27893347349fd51cc1911cb403682a7163373adacc565d11e2e4c')
+
+prepare() {
+    cd "${srcdir}"/diff-match-patch-${pkgver}
+    sed -i 's/\/usr\/bin\/python2.4/\/usr\/bin\/python2.7/' python2/diff_match_patch/*
+}
 
 package() {
-  depends=('python3')
+    depends=('python3')
 
-  cd "${srcdir}"/diff-match-patch-$pkgver
+    cd "${srcdir}"/diff-match-patch-$pkgver
 
-  python3 setup.py install --root="${pkgdir}" -O1
-  find "${pkgdir}" -name *_py2.* -delete
+    python3 setup.py install --root="${pkgdir}" -O1
+    #find "${pkgdir}" -name *_py2.* -delete
 }