You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: command.rb
    path of file: ./repos/vagrant/plugins/commands/up
    
    the code of the file until where you have to start completion: # Copyright (c) HashiCorp, Inc.
# SPDX-License-Identifier: BUSL-1.1

require 'optparse'
require 'set'

require "vagrant"

require File.expand_path("../start_mixins", __FIL
    
      def install_providers(names, provider: nil)
        # First create a set of all the providers we need to check for.
        # Most likely this will be a set of one.
        providers = Set.new
        with_target_vms(names, provider: provider) do |machine|
          # Check if we have this machine in the index
          entry    = @env.machine_index.get(machine.name.to_s)

          # Get the provider for this machine. This logic isn't completely
          # straightforward. If we have a forced provider, we always use
          # that no matter what. If we have an entry in the index (meaning
          # the machine may be created), we use that provider no matter
          # what since that will be used by the core. If we have none, then
          # we ask the Vagrant env what the default provider would be and use
          # that.
          #
          # Note that this logic is a bit redundant if we have "provider"
          # set but I think its probably cleaner to put this logic in one
          # place.
          p = provider
          p = entry.provider.to_sym if !p && entry
          p = @env.default_provider(
            machine: machine.name.to_sym, check_usable: false) if !p

          # Add it to the set
          providers.add(p)
        end

        # Go through and determine if we can install the providers
        providers.delete_if do |name|
          !@env.can_install_provider?(name)
        end

        # Install the providers if we have to
        providers.each do |name|
          # Find the provider. Ignore if we can't find it, this error
          # will pop up later in the process.
          parts = Vagrant.plugin("2").manager.providers[name]
          next if !parts

          # If the provider is already installed, then our work here is done
          cls = parts[0]
          next if cls.installed?

          # Some human-friendly output
          ui = Vagrant::UI::Prefixed.new(@env.ui, "")
          ui.output(I18n.t(
            "vagrant.installing_provider",
            provider: name.to_s))
          ui.detail(I18n.t("vagrant.installing_provider_detail"))

          # Install the provider
          @env.install_provider(name)
        end
      end
    end