Update documentation to mention bytes instead byte string and correct one

mentioned string to the accurate description of what type is required.

1 files changed, 4 insertions, 3 deletions

diff --git a/Doc/library/subprocess.rst b/Doc/library/subprocess.rst
index ad5a535..a0d8471 100644
--- a/Doc/library/subprocess.rst
+++ b/Doc/library/subprocess.rst
@@ -311,7 +311,7 @@ This module also defines the following shortcut functions:
 
 .. function:: check_output(*popenargs, timeout=None, **kwargs)
 
-   Run command with arguments and return its output as a byte string.
+   Run command with arguments and return its output as a bytes object.
 
    If the exit code was non-zero it raises a :exc:`CalledProcessError`.  The
    :exc:`CalledProcessError` object will have the return code in the
@@ -447,8 +447,9 @@ Instances of the :class:`Popen` class have the following methods:
 
    Interact with process: Send data to stdin.  Read data from stdout and stderr,
    until end-of-file is reached.  Wait for process to terminate.  The optional
-   *input* argument should be a byte string to be sent to the child process, or
-   ``None``, if no data should be sent to the child.
+   *input* argument should be data to be sent to the child process, or
+   ``None``, if no data should be sent to the child.  The type of *input*
+   must be bytes or, if *universal_newlines* was ``True``, a string.
 
    :meth:`communicate` returns a tuple ``(stdoutdata, stderrdata)``.