Merge pull request #220 from emtudo/patch-2

method gerar change to abstract

Author: eduardokum

src/Cnab/Remessa/AbstractRemessa.php

@@ -474,10 +474,7 @@ protected function valida(array $a)
      * @return string
      * @throws \Exception
      */
-    public function gerar()
-    {
-        throw new \Exception('Método não implementado');
-    }
+    abstract public function gerar();
 
     /**
      * Salva o arquivo no path informado
@@ -520,4 +517,4 @@ public function download($filename = null)
         header('Content-Disposition: attachment; filename="' . $filename . '"');
         echo $this->gerar();
     }
-}
+}