Parameters::value returns null on failure instead of throwing

README.md

@@ -218,7 +218,7 @@ echo $dictionary->toHttpValue(); //returns "a=?0, z=42.0"
 The `Parameters` instance exposes the following methods:
 
 - `Parameters::values` to list all existing Bare Items value as an array list;
-- `Parameters::value($key)` to return the value of the Bare Item associated to the `$key` or throw if the key is unknown or invalid;
+- `Parameters::value(string $key)` to return the value of the Bare Item associated to the `$key` or `null` if the key is unknown or invalid;
 - `Parameters::merge` also accepts iterable as associative key-value as part of the variadic signature.
 
 ```php
@@ -238,7 +238,7 @@ $parameters->merge(
     ['b' => 'false']
 );
 $parameters->toHttpValue(); // returns ;b="false";foo="foo"
-
+$parameters->value('unknown'); // returns null
 ```
 
 #### Lists

src/InnerListTest.php

@@ -142,9 +142,8 @@ public function it_can_access_its_parameter_values(): void
      */
     public function it_fails_to_access_unknown_parameter_values(): void
     {
-        $this->expectException(InvalidOffset::class);
-
         $instance = InnerList::fromList([false], ['foo' => 'bar']);
-        $instance->parameters->value('bar');
+
+        self::assertNull($instance->parameters->value('bar'));
     }
 }

src/ItemTest.php

@@ -236,10 +236,9 @@ public function it_can_access_its_parameter_values(): void
      */
     public function it_fails_to_access_unknown_parameter_values(): void
     {
-        $this->expectException(InvalidOffset::class);
-
         $instance = Item::fromHttpValue('1; a; b=?0');
-        $instance->parameters->value('bar');
+
+        self::assertNull($instance->parameters->value('bar'));
     }
 
     /**

src/Parameters.php

@@ -168,12 +168,10 @@ public function values(): array
         return array_map(fn (Item $item): Token|ByteSequence|float|int|bool|string => $item->value, $this->members);
     }
 
-    public function value(string $key): Token|ByteSequence|float|int|bool|string
+    public function value(string $key): Token|ByteSequence|float|int|bool|string|null
     {
-        self::validateKey($key);
-
         if (!array_key_exists($key, $this->members)) {
-            throw InvalidOffset::dueToKeyNotFound($key);
+            return null;
         }
 
         return $this->members[$key]->value;
@@ -314,9 +312,7 @@ public function prepend(string $key, Item|ByteSequence|Token|bool|int|float|stri
     public function merge(iterable ...$others): void
     {
         foreach ($others as $other) {
-            foreach ($other as $key => $value) {
-                $this->set($key, $value);
-            }
+            $this->members = [...$this->members, ...self::fromAssociative($other)->members];
         }
     }
 }