Document pngtobytes as returning bytes
@@ -46,7 +46,7 @@ def topngbytes(name, rows, x, y, **k):
Convenience function for creating a PNG file "in memory" as
a string. Creates a :class:`Writer` instance using the keyword
arguments, then passes `rows` to its :meth:`Writer.write` method.
- The resulting PNG file is returned as a string. `name` is used
+ The resulting PNG file is returned as bytes. `name` is used
to identify the file for debugging.
"""
