def king_positions
      king_locations = []

      @piece_locations.each do |piece, details|
        king_locations << piece if details.fetch(:type) == :king
      end

      king_locations
    end
def king_positions
      king_locations = []

      @piece_locations.each do |piece, details|
        king_locations << piece if details.fetch(:type) == :king
      end

      king_locations
    end
Search piece manifest for kings. Remove them from the list of positions returned
 from the Move module (so that players cannot take the "king" type piece)