Add doctests to some of this stuff.

1 files changed, 29 insertions, 6 deletions

diff --git a/list_utils.py b/list_utils.py
index 7d3355c..993ca8a 100644
--- a/list_utils.py
+++ b/list_utils.py
@@ -5,16 +5,28 @@ from typing import Any, Iterator, List
 
 
 def shard(lst: List[Any], size: int) -> Iterator[Any]:
-    """Yield successive size-sized shards from lst."""
+    """
+    Yield successive size-sized shards from lst.
+
+    >>> for sublist in shard([1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12], 3):
+    ...     [_ for _ in sublist]
+    [1, 2, 3]
+    [4, 5, 6]
+    [7, 8, 9]
+    [10, 11, 12]
+
+    """
     for x in range(0, len(lst), size):
         yield islice(lst, x, x + size)
 
 
 def flatten(lst: List[Any]) -> List[Any]:
-    """Flatten out a list:
+    """
+    Flatten out a list:
+
+    >>> flatten([ 1, [2, 3, 4, [5], 6], 7, [8, [9]]])
+    [1, 2, 3, 4, 5, 6, 7, 8, 9]
 
-        >>> flatten([ 1, [2, 3, 4, [5], 6], 7, [8, [9]]])
-        [1, 2, 3, 4, 5, 6, 7, 8, 9]
     """
     if len(lst) == 0:
         return lst
@@ -24,6 +36,17 @@ def flatten(lst: List[Any]) -> List[Any]:
 
 
 def prepend(item: Any, lst: List[Any]) -> List[Any]:
-    """Prepend an item to a list."""
-    lst = list.insert(0, item)
+    """
+    Prepend an item to a list.
+
+    >>> prepend('foo', ['bar', 'baz'])
+    ['foo', 'bar', 'baz']
+
+    """
+    lst.insert(0, item)
     return lst
+
+
+if __name__ == '__main__':
+    import doctest
+    doctest.testmod()