def specs_from_names(names)
      names.map do |name|
        spec = available_spec(name)
        fail "#{name} was not found" if spec.nil?
        spec
      end
    end
def specs_from_names(names)
      names.map do |name|
        spec = available_spec(name)
        fail "#{name} was not found" if spec.nil?
        spec
      end
    end
List of available gem specifications with the given names.
 Raises an error if a name cannot be found.