Для openSUSE Tumbleweed запустите от имени root:
zypper addrepo https://download.opensuse.org/repositories/devel:languages:python/openSUSE_Tumbleweed/devel:languages:python.repo
zypper refresh
zypper install python-pyRFC3339
Для openSUSE Factory zSystems запустите от имени root:
zypper addrepo https://download.opensuse.org/repositories/devel:languages:python/openSUSE_Factory_zSystems/devel:languages:python.repo
zypper refresh
zypper install python-pyRFC3339
Для openSUSE Factory PowerPC запустите от имени root:
zypper addrepo https://download.opensuse.org/repositories/devel:languages:python/openSUSE_Factory_PowerPC/devel:languages:python.repo
zypper refresh
zypper install python-pyRFC3339
Для 15.6 запустите от имени root:
zypper addrepo https://download.opensuse.org/repositories/devel:languages:python/15.6/devel:languages:python.repo
zypper refresh
zypper install python-pyRFC3339