Snapcraft YAML file build-environment property "does not match the required schema" error

I literally copied this:

Issues while validating snapcraft.yaml: The 'parts/waterfox/build-environment' property does not match the required schema: [{'PATH': '/snap/gnome-3-34-1804-sdk/current/usr/bin:$PATH'}, {'XDG_DATA_DIRS': '$SNAPCRAFT_STAGE/usr/share:/snap/gnome-3-34-1804-sdk/current/usr/share:/usr/share:$XDG_DATA_DIRS'}, {'LD_LIBRARY_PATH': '/snap/gnome-3-34-1804-sdk/current/lib/$SNAPCRAFT_ARCH_TRIPLET:/snap/gnome-3-34-1804-sdk/current/usr/lib/$SNAPCRAFT_ARCH_TRIPLET:/snap/gnome-3-34-1804-sdk/current/usr/lib:/snap/gnome-3-34-1804-sdk/current/usr/lib/vala-current:$LD_LIBRARY_PATH'}, {'PKG_CONFIG_PATH': '/snap/gnome-3-34-1804-sdk/current/usr/lib/$SNAPCRAFT_ARCH_TRIPLET/pkgconfig:/snap/gnome-3-34-1804-sdk/current/usr/lib/pkgconfig:/snap/gnome-3-34-1804-sdk/current/usr/share/pkgconfig:$PKG_CONFIG_PATH'}, {'GETTEXTDATADIRS': '/snap/gnome-3-34-1804-sdk/current/usr/share/gettext-current:$GETTEXTDATADIRS'}, {'GDK_PIXBUF_MODULE_FILE': '/snap/gnome-3-34-1804-sdk/current/usr/lib/$SNAPCRAFT_ARCH_TRIPLET/gdk-pixbuf-current/loaders.cache'}, {'PYTHONPATH': '/snap/gnome-3-34-1804-sdk/current/usr/lib/python3/dist-packages${PYTHONPATH:+:$PYTHONPATH}'}, OrderedDict([('PATH', '/snap/gnome-3-34-1804-sdk/current/usr/bin:$PATH')]), OrderedDict([('XDG_DATA_DIRS', '/snap/gnome-3-34-1804-sdk/current/usr/share:/usr/share:$XDG_DATA_DIRS')]), OrderedDict([('LD_LIBRARY_PATH', '/snap/gnome-3-34-1804-sdk/current/lib/$SNAPCRAFT_ARCH_TRIPLET:/snap/gnome-3-34-1804-sdk/current/usr/lib/$SNAPCRAFT_ARCH_TRIPLET:/snap/gnome-3-34-1804-sdk/current/usr/lib:/snap/gnome-3-34-1804-sdk/current/usr/lib/vala-current:$LD_LIBRARY_PATH')]), OrderedDict([('PKG_CONFIG_PATH', '/snap/gnome-3-34-1804-sdk/current/usr/lib/$SNAPCRAFT_ARCH_TRIPLET/pkgconfig:/snap/gnome-3-34-1804-sdk/current/usr/lib/pkgconfig:/snap/gnome-3-34-1804-sdk/current/usr/share/pkgconfig:$PKG_CONFIG_PATH')]), OrderedDict([('GETTEXTDATADIRS', '/snap/gnome-3-34-1804-sdk/current/usr/share/gettext-current:$GETTEXTDATADIRS')]), OrderedDict([('GDK_PIXBUF_MODULE_FILE', '/snap/gnome-3-34-1804-sdk/current/usr/lib/$SNAPCRAFT_ARCH_TRIPLET/gdk-pixbuf-current/loaders.cache')])] has non-unique elements

Here’s the Snapcraft YAML file. I didn’t even change anything there, just the version #.

Everything except PYTHONPATH is duplicated by the gnome-3-34 extension, so it is quite correct when it states that you have duplicate items.

So get rid of these:

      - PATH: /snap/gnome-3-34-1804-sdk/current/usr/bin:$PATH
      - XDG_DATA_DIRS: /snap/gnome-3-34-1804-sdk/current/usr/share:/usr/share:$XDG_DATA_DIRS
      - LD_LIBRARY_PATH: /snap/gnome-3-34-1804-sdk/current/lib/$SNAPCRAFT_ARCH_TRIPLET:/snap/gnome-3-34-1804-sdk/current/usr/lib/$SNAPCRAFT_ARCH_TRIPLET:/snap/gnome-3-34-1804-sdk/current/usr/lib:/snap/gnome-3-34-1804-sdk/current/usr/lib/vala-current:$LD_LIBRARY_PATH
      - PKG_CONFIG_PATH: /snap/gnome-3-34-1804-sdk/current/usr/lib/$SNAPCRAFT_ARCH_TRIPLET/pkgconfig:/snap/gnome-3-34-1804-sdk/current/usr/lib/pkgconfig:/snap/gnome-3-34-1804-sdk/current/usr/share/pkgconfig:$PKG_CONFIG_PATH
      - GETTEXTDATADIRS: /snap/gnome-3-34-1804-sdk/current/usr/share/gettext-current:$GETTEXTDATADIRS
      - GDK_PIXBUF_MODULE_FILE: /snap/gnome-3-34-1804-sdk/current/usr/lib/$SNAPCRAFT_ARCH_TRIPLET/gdk-pixbuf-current/loaders.cache