Laravel Collection Public API: sum
…Adam ' , 40 ' Xander ' , 41 ' Wim ' , 42 ' Mitchell ' , 43 ' Gabriela ' , 44 ' Matt ' , 45 ' Frank ' , 46 ' Hannes ' , 47 ' Kirk ' 48 ] 49 ] , 50 [ 51 ' year ' => ' 2013 ' , 52 ' speakers ' => [ 53 ' Taylor ' , 54 ' Fabien ' , 55 ' Phill ' , 56 '...