    # File lib/chef/version_constraint.rb, line 28
        def initialize(constraint_spec=DEFAULT_CONSTRAINT)
          case constraint_spec
          when nil
            parse(DEFAULT_CONSTRAINT)
          when Array
            parse_from_array(constraint_spec)
          when String
            parse(constraint_spec)
          else
            msg = "VersionConstraint should be created from a String. You gave: #{constraint_spec.inspect}"
            raise Chef::Exceptions::InvalidVersionConstraint, msg
          end
        end