# File lib/fog/core/attributes.rb, line 167 def requires(*args) missing = [] for arg in [:connection] | args unless send("#{arg}") || attributes.has_key?(arg) missing << arg end end unless missing.empty? if missing.length == 1 raise(ArgumentError, "#{missing.first} is required for this operation") else raise(ArgumentError, "#{missing[0...-1].join(", ")} and #{missing[-1]} are required for this operation") end end end