package Ġsolid _ design _ pr incip les . dependency _ in version _ pr incip le Ċ Ċ // ĠA . ĠHigh - level Ġmodules Ġshould Ġnot Ġdepend Ġon Ġlow - level Ġmodules . Ċ // ĠBoth Ġshould Ġdepend Ġon Ġab stractions . Ċ Ċ // ĠB . ĠAb stractions Ġshould Ġnot Ġdepend Ġon Ġdetails . Ċ // ĠDetails Ġshould Ġdepend Ġon Ġab stractions . Ċ Ċ fun Ġmain () Ġ{ ĊĠĠĠ Ġval Ġparent Ġ= ĠPerson (" John ") ĊĠĠĠ Ġval Ġchild 1 Ġ= ĠPerson (" Ch ris ") ĊĠĠĠ Ġval Ġchild 2 Ġ= ĠPerson (" Mat t ") ĊĊĠĠĠ Ġval Ġrelationships Ġ= ĠRelationship s () ĊĠĠĠ Ġrelationships . add Parent And Child ( parent , Ġchild 1 ) ĊĠĠĠ Ġrelationships . add Parent And Child ( parent , Ġchild 2 ) ĊĊĠĠĠ Ġval Ġresearch Ġ= ĠResearch ( relationships ) Ċ } Ċ