```ruby
module DbCharmer
  module DbMagic
    module ClassMethods
      def db_magic(opt = {})
        # Make sure we could use our connections management here
        hijack_connection!

        # Should requested connections exist in the config?
        should_exist = opt[:should_exist] || DbCharmer.connections_should_exist?

        # Main connection management
        db_magic_connection(opt[:connection], should_exist) if opt[:connection]

        # Set up slaves pool
        opt[:slaves] ||= []
        opt[:slaves] << opt[:slave] if opt[:slave]
        db_magic_slaves(opt[:slaves], should_exist)

        self.extend(DbCharmer::MultiDbProxy::MasterSlaveClassMethods)
      end

    private

      def db_magic_connection(conn, should_exist = false)
        switch_connection_to(conn, should_exist)
      end

      def db_magic_slaves(slaves, should_exist = false)
        self.db_charmer_slaves = slaves.collect do |slave|
          coerce_to_connection_proxy(slave, should_exist)
        end

        self.extend(DbCharmer::FinderOverrides::ClassMethods)
        self.send(:include, DbCharmer::FinderOverrides::InstanceMethods)
      end
    end
  end
end
```

Enable master-slave stuff only when there are some slaves
user
```ruby
module DbCharmer
  module DbMagic
    module ClassMethods
      def db_magic(opt = {})
        # Make sure we could use our connections management here
        hijack_connection!

        # Should requested connections exist in the config?
        should_exist = opt[:should_exist] || DbCharmer.connections_should_exist?

        # Main connection management
        db_magic_connection(opt[:connection], should_exist) if opt[:connection]

        # Set up slaves pool
        opt[:slaves] ||= []
        opt[:slaves] << opt[:slave] if opt[:slave]
        db_magic_slaves(opt[:slaves], should_exist) if opt[:slaves].any?
      end

    private

      def db_magic_connection(conn, should_exist = false)
        switch_connection_to(conn, should_exist)
      end

      def db_magic_slaves(slaves, should_exist = false)
        self.db_charmer_slaves = slaves.collect do |slave|
          coerce_to_connection_proxy(slave, should_exist)
        end

        self.extend(DbCharmer::FinderOverrides::ClassMethods)
        self.send(:include, DbCharmer::FinderOverrides::InstanceMethods)
        self.extend(DbCharmer::MultiDbProxy::MasterSlaveClassMethods)
      end
    end
  end
end
```
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