Refactor imports and improve code formatting in dataset and trainer modules

src/f5_tts/model/dataset.py

@@ -1,5 +1,4 @@
 import json
-import random
 from importlib.resources import files
 
 import torch

src/f5_tts/model/trainer.py

@@ -279,11 +279,11 @@ class Trainer:
             self.accelerator.even_batches = False
             sampler = SequentialSampler(train_dataset)
             batch_sampler = DynamicBatchSampler(
-                sampler, 
-                self.batch_size, 
-                max_samples=self.max_samples, 
+                sampler,
+                self.batch_size,
+                max_samples=self.max_samples,
                 random_seed=resumable_with_seed,  # This enables reproducible shuffling
-                drop_last=False
+                drop_last=False,
             )
             train_dataloader = DataLoader(
                 train_dataset,
@@ -334,7 +334,7 @@ class Trainer:
                 current_dataloader = train_dataloader
 
             # Set epoch for the batch sampler if it exists
-            if hasattr(train_dataloader, 'batch_sampler') and hasattr(train_dataloader.batch_sampler, 'set_epoch'):
+            if hasattr(train_dataloader, "batch_sampler") and hasattr(train_dataloader.batch_sampler, "set_epoch"):
                 train_dataloader.batch_sampler.set_epoch(epoch)
 
             progress_bar = tqdm(