rg lift_execute_process

let mut env: BTreeMap<String, String> = BTreeMap::new();
    let env_var_parts = externs::project_multi_strs(&value, "env");
    if env_var_parts.len() % 2 != 0 {
      return Err("Error parsing env: odd number of parts".to_owned());
    }
    for i in 0..(env_var_parts.len() / 2) {
      env.insert(
        env_var_parts[2 * i].clone(),
        env_var_parts[2 * i + 1].clone(),
      );
    }