diff --git a/tablib/helpers.py b/tablib/helpers.py
index f20700d..0a91e56 100644
--- a/tablib/helpers.py
+++ b/tablib/helpers.py
@@ -16,5 +16,6 @@ class Struct(object):
 def piped():
 	"""Returns piped input via stdin, else False."""
 	with sys.stdin as stdin:
+		# TTY is only way to detect if stdin contains data
 		return stdin.read() if not stdin.isatty() else None