def _format_stack(frame):
"""
Pretty-print the stack of `frame` like logging would.
"""
sio = StringIO()
sio.write('Stack (most recent call last):\n')
traceback.print_stack(frame, file=sio)
sinfo = sio.getvalue()
if sinfo[-1] == '\n':
sinfo = sinfo[:-1]
sio.close()
return sinfo
