Document what IterBlock does in code

Signed-off-by: Ben Browning <[email protected]>

src/instructlab/sdg/blocks/iterblock.py

@@ -17,6 +17,21 @@
 # This is part of the public API.
 @BlockRegistry.register("IterBlock")
 class IterBlock(Block):
+    """
+    Call another block multiple times for a single set of input
+    samples, concatening the results of each iteration's call to that
+    other block in the final returned output.
+
+    Args:
+        num_iters: The number of times to iterate over the block
+        block_type: The type of the other block to call (ie LLMBlock)
+        block_config: Any necessary configuration that will get passed to the
+                      other block to properly configure it.
+
+    Returns:
+        A Dataset containing all output samples from each iteration
+    """
+
     def __init__(
         self,
         ctx,