feat(openai_dart): Support new completion API functionality (#199)

- Support `seed`

> The new seed parameter enables reproducible outputs by making the model return consistent completions most of the time. This beta feature is useful for use cases such as replaying requests for debugging, writing more comprehensive unit tests, and generally having a higher degree of control over the model behavior. We at OpenAI have been using this feature internally for our own unit tests and have found it invaluable. We’re excited to see how developers will use it.

packages/openai_dart/lib/src/generated/schema/create_completion_request.dart

@@ -42,7 +42,7 @@ class CreateCompletionRequest with _$CreateCompletionRequest {
 
     /// Modify the likelihood of specified tokens appearing in the completion.
     ///
-    /// Accepts a json object that maps tokens (specified by their token ID in the GPT tokenizer) to an associated bias value from -100 to 100. You can use this [tokenizer tool](https://platform.openai.com/tokenizer?view=bpe) (which works for both GPT-2 and GPT-3) to convert text to token IDs. Mathematically, the bias is added to the logits generated by the model prior to sampling. The exact effect will vary per model, but values between -1 and 1 should decrease or increase likelihood of selection; values like -100 or 100 should result in a ban or exclusive selection of the relevant token.
+    /// Accepts a JSON object that maps tokens (specified by their token ID in the GPT tokenizer) to an associated bias value from -100 to 100. You can use this [tokenizer tool](https://platform.openai.com/tokenizer?view=bpe) (which works for both GPT-2 and GPT-3) to convert text to token IDs. Mathematically, the bias is added to the logits generated by the model prior to sampling. The exact effect will vary per model, but values between -1 and 1 should decrease or increase likelihood of selection; values like -100 or 100 should result in a ban or exclusive selection of the relevant token.
     ///
     /// As an example, you can pass `{"50256": -100}` to prevent the <|endoftext|> token from being generated.
     @JsonKey(name: 'logit_bias', includeIfNull: false)
@@ -72,6 +72,11 @@ class CreateCompletionRequest with _$CreateCompletionRequest {
     @Default(0.0)
     double? presencePenalty,
 
+    /// If specified, our system will make a best effort to sample deterministically, such that repeated requests with the same `seed` and parameters should return the same result.
+    ///
+    /// Determinism is not guaranteed, and you should refer to the `system_fingerprint` response parameter to monitor changes in the backend.
+    @JsonKey(includeIfNull: false) int? seed,
+
     /// Up to 4 sequences where the API will stop generating further tokens. The returned text will not contain the stop sequence.
     @_CompletionStopConverter()
     @JsonKey(includeIfNull: false)
@@ -113,6 +118,7 @@ class CreateCompletionRequest with _$CreateCompletionRequest {
     'max_tokens',
     'n',
     'presence_penalty',
+    'seed',
     'stop',
     'stream',
     'suffix',
@@ -137,6 +143,8 @@ class CreateCompletionRequest with _$CreateCompletionRequest {
   static const presencePenaltyDefaultValue = 0.0;
   static const presencePenaltyMinValue = -2.0;
   static const presencePenaltyMaxValue = 2.0;
+  static const seedMinValue = -9223372036854775808;
+  static const seedMaxValue = 9223372036854775807;
   static const temperatureDefaultValue = 1.0;
   static const temperatureMinValue = 0.0;
   static const temperatureMaxValue = 2.0;
@@ -181,6 +189,12 @@ class CreateCompletionRequest with _$CreateCompletionRequest {
     if (presencePenalty != null && presencePenalty! > presencePenaltyMaxValue) {
       return "The value of 'presencePenalty' cannot be > $presencePenaltyMaxValue";
     }
+    if (seed != null && seed! < seedMinValue) {
+      return "The value of 'seed' cannot be < $seedMinValue";
+    }
+    if (seed != null && seed! > seedMaxValue) {
+      return "The value of 'seed' cannot be > $seedMaxValue";
+    }
     if (temperature != null && temperature! < temperatureMinValue) {
       return "The value of 'temperature' cannot be < $temperatureMinValue";
     }
@@ -209,6 +223,7 @@ class CreateCompletionRequest with _$CreateCompletionRequest {
       'max_tokens': maxTokens,
       'n': n,
       'presence_penalty': presencePenalty,
+      'seed': seed,
       'stop': stop,
       'stream': stream,
       'suffix': suffix,

packages/openai_dart/lib/src/generated/schema/create_completion_response.dart

@@ -27,8 +27,14 @@ class CreateCompletionResponse with _$CreateCompletionResponse {
     /// The model used for completion.
     required String model,
 
+    /// This fingerprint represents the backend configuration that the model runs with.
+    ///
+    /// Can be used in conjunction with the `seed` request parameter to understand when backend changes have been made that might impact determinism.
+    @JsonKey(name: 'system_fingerprint', includeIfNull: false)
+    String? systemFingerprint,
+
     /// The object type, which is always "text_completion"
-    required String object,
+    required CreateCompletionResponseObject object,
 
     /// Usage statistics for the completion request.
     @JsonKey(includeIfNull: false) CompletionUsage? usage,
@@ -44,6 +50,7 @@ class CreateCompletionResponse with _$CreateCompletionResponse {
     'choices',
     'created',
     'model',
+    'system_fingerprint',
     'object',
     'usage'
   ];
@@ -60,8 +67,19 @@ class CreateCompletionResponse with _$CreateCompletionResponse {
       'choices': choices,
       'created': created,
       'model': model,
+      'system_fingerprint': systemFingerprint,
       'object': object,
       'usage': usage,
     };
   }
 }
+
+// ==========================================
+// ENUM: CreateCompletionResponseObject
+// ==========================================
+
+/// The object type, which is always "text_completion"
+enum CreateCompletionResponseObject {
+  @JsonValue('text_completion')
+  textCompletion,
+}