Let the Filter operation use a variadic parameter.

src/Collection.php

@@ -126,9 +126,9 @@ public static function empty(): CollectionInterface
     /**
      * {@inheritdoc}
      */
-    public function filter(callable $callback = null): CollectionInterface
+    public function filter(callable ...$callbacks): CollectionInterface
     {
-        return $this->run(Filter::with($callback));
+        return $this->run(Filter::with($callbacks));
     }
 
     /**

src/Contract/Collection.php

@@ -75,11 +75,11 @@ public function count(): int;
     /**
      * Run a filter over each of the items.
      *
-     * @param null|callable $callback
+     * @param callable ...$callbacks
      *
      * @return \drupol\collection\Contract\Collection
      */
-    public function filter(callable $callback = null): self;
+    public function filter(callable ...$callbacks): self;
 
     /**
      * Get the first item from the collection passing the given truth test.

src/Operation/Filter.php

@@ -17,19 +17,21 @@ final class Filter extends Operation
      */
     public function run(CollectionInterface $collection): CollectionInterface
     {
-        $callback = $this->parameters[0];
+        [$callbacks] = $this->parameters;
 
-        if (null === $callback) {
-            $callback = static function ($value) {
+        if ([] === $callbacks) {
+            $callbacks[] = static function ($value) {
                 return $value;
             };
         }
 
         return Collection::with(
-            static function () use ($callback, $collection) {
-                foreach ($collection->getIterator() as $key => $value) {
-                    if (true === (bool) $callback($value, $key)) {
-                        yield $key => $value;
+            static function () use ($callbacks, $collection) {
+                foreach ($callbacks as $callback) {
+                    foreach ($collection->getIterator() as $key => $value) {
+                        if (true === (bool) $callback($value, $key)) {
+                            yield $key => $value;
+                        }
                     }
                 }
             }