Multiple appends or set of the same variable inside the same if do not work in Command Prompt

[traversaro]

I have (in https://github.com/traversaro/robotology-superbuild/blob/master/conda/multisheller/icub-models_activate.msh) a script that does:

if_(is_set("COMSPEC")).then_([
	sys.list_append("GAZEBO_MODEL_PATH", path.join(env("CONDA_PREFIX"), "Library\\share\\gazebo\\models")),
	sys.list_append("GAZEBO_MODEL_PATH", path.join(env("CONDA_PREFIX"), "Library\\share\\iCub\\robots")),
	sys.list_append("GAZEBO_MODEL_PATH", path.join(env("CONDA_PREFIX"), "Library\\share"))
]).else_([
	sys.list_append("GAZEBO_MODEL_PATH", path.join(env("CONDA_PREFIX"), "share/gazebo/models")),
	sys.list_append("GAZEBO_MODEL_PATH", path.join(env("CONDA_PREFIX"), "share/iCub/robots")),
	sys.list_append("GAZEBO_MODEL_PATH", path.join(env("CONDA_PREFIX"), "share"))
])

in Command Prompt, for some reason this script does not work correctly (only the last set works), while the following works fine:

if_(is_set("COMSPEC")).then_([
	sys.list_append("GAZEBO_MODEL_PATH", path.join(env("CONDA_PREFIX"), "Library\\share\\gazebo\\models"))
]).else_([
	sys.list_append("GAZEBO_MODEL_PATH", path.join(env("CONDA_PREFIX"), "share/gazebo/models")),
])

if_(is_set("COMSPEC")).then_([
	sys.list_append("GAZEBO_MODEL_PATH", path.join(env("CONDA_PREFIX"), "Library\\share\\iCub\\robots"))
]).else_([
	sys.list_append("GAZEBO_MODEL_PATH", path.join(env("CONDA_PREFIX"), "share/iCub/robots"))
])

if_(is_set("COMSPEC")).then_([
	sys.list_append("GAZEBO_MODEL_PATH", path.join(env("CONDA_PREFIX"), "Library\\share"))
]).else_([
	sys.list_append("GAZEBO_MODEL_PATH", path.join(env("CONDA_PREFIX"), "share"))
])