invert_predicate

# File activerecord/lib/active_record/relation/where_clause.rb, line 122
        def invert_predicate(node)
          case node
          when NilClass
            raise ArgumentError, "Invalid argument for .where.not(), got nil."
          when Arel::Nodes::In
            Arel::Nodes::NotIn.new(node.left, node.right)
          when Arel::Nodes::Equality
            Arel::Nodes::NotEqual.new(node.left, node.right)
          when String
            Arel::Nodes::Not.new(Arel::Nodes::SqlLiteral.new(node))
          else
            Arel::Nodes::Not.new(node)
          end
        end