FunctionNode failing when printing lua code from clipboard register

[dhulihan]

Hi, I'm trying to create a markdown snippet that prints the contents of my clipboard register (*) in a fenced code block.

	s("`p", {
		isn(0, {
			t({ "", "" }),
			t({ "\t```" }),
			i(1, "language"),
			t({ "", "\t" }),
			f(function()
				return vim.fn.getreg("*")
			end, {}),
			t({ "", "\t```" }),
		}, "$PARENT_INDENT"),
	}),

This works great for most languages:

* This is an example`p

Turns into:

* This is an example
    ```go
    fmt.Println("hello world")
    ```

However, say I have this lua code in my clipboard:

local register_content = vim.fn.getreg('a')

I get:

share/nvim/lazy/LuaSnip/lua/luasnip/nodes/node.lua:609: [LuaSnip Failed]: { "local register_content = vim.fn.getreg('a')\n"
}

and LuaSnip stops working entirely until I restart neovim.

It seems like f(...) is evaluating the content of the text being returned by a lua function, but maybe I'm missing something here.