pyenv/plugins/pyenv-version-ext/bin/pyenv-sh-push

#!/usr/bin/env bash
# Usage: pyenv push <version>
set -e
[ -n "$PYENV_DEBUG" ] && set -x

IFS=: PYENV_VERSION_NAMES=($(pyenv-version-name))
versions=("$@")
PYENV_VERSION_NAMES=("${PYENV_VERSION_NAMES[@]}" "${versions[@]}")

if [ -n "$PYENV_VERSION" ]; then
  IFS=: PYENV_VERSION="${PYENV_VERSION_NAMES[*]}"
  echo "export PYENV_VERSION=\"${PYENV_VERSION}\""
else
  pyenv-version-file-write "$(pyenv-version-file)" "${PYENV_VERSION_NAMES[@]}"
fi