Gem.paths=

# File tmp/rubies/ruby-3.0.5/lib/rubygems.rb, line 386
  def self.paths=(env)
    clear_paths
    target = {}
    env.each_pair do |k,v|
      case k
      when 'GEM_HOME', 'GEM_PATH', 'GEM_SPEC_CACHE'
        case v
        when nil, String
          target[k] = v
        when Array
          unless Gem::Deprecate.skip
            warn <<-EOWARN
Array values in the parameter to `Gem.paths=` are deprecated.
Please use a String or nil.
An Array (#{env.inspect}) was passed in from #{caller[3]}
            EOWARN
          end
          target[k] = v.join File::PATH_SEPARATOR
        end
      else
        target[k] = v
      end
    end
    @paths = Gem::PathSupport.new ENV.to_hash.merge(target)
    Gem::Specification.dirs = @paths.path
  end