add typehints for torchvision.datasets.semeion (#2534)

torchvision/datasets/semeion.py

@@ -2,6 +2,7 @@ from PIL import Image
 import os
 import os.path
 import numpy as np
+from typing import Any, Callable, Optional, Tuple
 from .vision import VisionDataset
 from .utils import download_url, check_integrity
 
@@ -23,7 +24,13 @@ class SEMEION(VisionDataset):
     filename = "semeion.data"
     md5_checksum = 'cb545d371d2ce14ec121470795a77432'
 
-    def __init__(self, root, transform=None, target_transform=None, download=True):
+    def __init__(
+            self,
+            root: str,
+            transform: Optional[Callable] = None,
+            target_transform: Optional[Callable] = None,
+            download: bool = True,
+    ) -> None:
         super(SEMEION, self).__init__(root, transform=transform,
                                       target_transform=target_transform)
 
@@ -44,7 +51,7 @@ class SEMEION(VisionDataset):
         self.data = np.reshape(self.data, (-1, 16, 16))
         self.labels = np.nonzero(data[:, 256:])[1]
 
-    def __getitem__(self, index):
+    def __getitem__(self, index: int) -> Tuple[Any, Any]:
         """
         Args:
             index (int): Index
@@ -65,17 +72,17 @@ class SEMEION(VisionDataset):
 
         return img, target
 
-    def __len__(self):
+    def __len__(self) -> int:
         return len(self.data)
 
-    def _check_integrity(self):
+    def _check_integrity(self) -> bool:
         root = self.root
         fpath = os.path.join(root, self.filename)
         if not check_integrity(fpath, self.md5_checksum):
             return False
         return True
 
-    def download(self):
+    def download(self) -> None:
         if self._check_integrity():
             print('Files already downloaded and verified')
             return