openSUSE Tumbleweed の場合は、 root で下記のコマンドを実行してください:
zypper addrepo https://download.opensuse.org/repositories/home:alarrosa:branches:devel:languages:python/openSUSE_Tumbleweed/home:alarrosa:branches:devel:languages:python.repo
zypper refresh
zypper install python-WTForms
openSUSE Factory の場合は、 root で下記のコマンドを実行してください:
zypper addrepo https://download.opensuse.org/repositories/home:alarrosa:branches:devel:languages:python/openSUSE_Factory/home:alarrosa:branches:devel:languages:python.repo
zypper refresh
zypper install python-WTForms
15.6 の場合は、 root で下記のコマンドを実行してください:
zypper addrepo https://download.opensuse.org/repositories/home:alarrosa:branches:devel:languages:python/15.6/home:alarrosa:branches:devel:languages:python.repo
zypper refresh
zypper install python-WTForms