import { type IEnvVarValueHandler } from "https://dotland.deno.dev/x/cliffy@v0.20.0/command/types.ts";
definition: (val: T) => unknown
x/cliffy/command/types.ts>IEnvVarValueHandler
import { type IEnvVarValueHandler } from "https://dotland.deno.dev/x/cliffy@v0.20.0/command/types.ts";