add abstract transform module

mu_map/dataset/transform.py

+from typing import List, Tuple
+
+
+from torch import Tensor
+
+
+class Transform:
+    def __call__(
+        self, inputs: Tensor, outputs_expected: Tensor
+    ) -> Tuple[Tensor, Tensor]:
+        return inputs, outputs_expected
+
+
+class SequenceTransform(Transform):
+    def __init__(self, transforms: List[Transform]):
+        self.transforms = transforms
+
+    def __call__(
+        self, inputs: Tensor, outputs_expected: Tensor
+    ) -> Tuple[Tensor, Tensor]:
+        for transforms in self.transforms:
+            inputs, outputs_expected = transforms(inputs, outputs_expected)
+        return inputs, outputs_expected