add random placeholder.

tat/compat.py

@@ -321,3 +321,30 @@ def exponential(self: T, pairs: set[tuple[str, str]], step: int | None = None) -
     "Compat Interface: Get the exponential tensor of this tensor."
     # pylint: disable=unused-argument
     return origin_exponential(self, pairs)
+
+
+# Random utility
+
+
+class CompatRandom:
+    """
+    Fake module for compat random utility in TAT.
+    """
+
+    def __init__(self: CompatRandom) -> None:
+        pass
+
+    def uniform_int(self: CompatRandom, low: int, high: int) -> typing.Callable[[], int]:
+        return staticmethod(lambda: 0)
+
+    def uniform_real(self: CompatRandom, low: float, high: float) -> typing.Callable[[], float]:
+        return staticmethod(lambda: 0.0)
+
+    def normal(self: CompatRandom, mean: float, stddev: float) -> typing.Callable[[], float]:
+        return staticmethod(lambda: 0.0)
+
+    def seed(self: CompatRandom, new_seed: int) -> None:
+        pass
+
+
+random = CompatRandom()