add example functions to default worker (#210)

scripts/example_functions.py

@@ -0,0 +1,25 @@
+import ray
+import numpy as np
+from typing import List
+
+@ray.remote([int], [float])
+def estimate_pi(n):
+  x = np.random.uniform(size=n)
+  y = np.random.uniform(size=n)
+  return 4 * np.mean(x ** 2 + y ** 2 < 1)
+
+@ray.remote([int], [int])
+def increment(x):
+  return x + 1
+
+@ray.remote([List[int]], [np.ndarray])
+def zeros(shape):
+  return np.zeros(shape)
+
+@ray.remote([np.ndarray, np.ndarray], [np.ndarray])
+def dot(a, b):
+  return np.dot(a, b)
+
+@ray.remote([], [])
+def throw_exception():
+  raise Exception("This function intentionally failed.")