help using guix size command w/ local file definition

[chris]

How does one use `guix size` with a local file package definition?

I have copied the `vifm` package definition here to a local file 
https://git.savannah.gnu.org/cgit/guix.git/tree/gnu/packages/vim.scm?id=master#n916

Using `guix size --load-path` as described here fails 
https://guix.gnu.org/manual/en/html_node/Invoking-guix-size.html
```
$ guix size --load-path=$HOME/software/vifm-local/ vifm-local
guix size: error: no available substitute information for 
'/gnu/store/vx189rcgy4b8lw1acw14cki9lm4jz9jn-vifm-local-0.13'
$ guix size --substitute-urls="" --load-path=$HOME/software/vifm-local/ 
vifm-local
guix size: error: no available substitute information for 
'/gnu/store/vx189rcgy4b8lw1acw14cki9lm4jz9jn-vifm-local-0.13'
```

Another question, as guix's vifm input list includes `libx11`, shouldn't x11 
appear in the size listing?
https://git.savannah.gnu.org/cgit/guix.git/tree/gnu/packages/vim.scm?id=master#n916
```
$ guix size vifm
store item                                total    self
/gnu/store/lj[...]f8-perl-5.36.0            152.2    59.4  34.9%
/gnu/store/gs[...]i3-glibc-2.35              40.6    38.8  22.8%
/gnu/store/93[...]yk-gcc-11.3.0-lib          75.3    34.7  20.4%
/gnu/store/a5[...]5c-coreutils-9.1           91.8    16.5   9.7%
/gnu/store/gr[...]hq-file-5.44               85.8     8.1   4.8%
/gnu/store/bc[...]gy-ncurses-6.2.20210619    81.2     5.9   3.5%
/gnu/store/gz[...]vg-vifm-0.13              170.3     2.7   1.6%
/gnu/store/zz[...]a7-bash-static-5.1.16       1.8     1.8   1.1%
/gnu/store/6k[...]wj-xz-5.2.8                77.7     1.4   0.8%
/gnu/store/ri[...]4k-bash-minimal-5.1.16     41.6     1.0   0.6%
total: 170.3 MiB
```

Thanks for any reply :)