def invoke_prerequisites(task_args, invocation_chain) # :nodoc:
      if application.options.always_multitask
        invoke_prerequisites_concurrently(task_args, invocation_chain)
      else
        prerequisite_tasks.each { |p|
          prereq_args = task_args.new_scope(p.arg_names)
          p.invoke_with_call_chain(prereq_args, invocation_chain)
        }
      end
    end
def invoke_prerequisites(task_args, invocation_chain) # :nodoc:
      if application.options.always_multitask
        invoke_prerequisites_concurrently(task_args, invocation_chain)
      else
        prerequisite_tasks.each { |p|
          prereq_args = task_args.new_scope(p.arg_names)
          p.invoke_with_call_chain(prereq_args, invocation_chain)
        }
      end
    end
Invoke all the prerequisites of a task.