sys command results in error #955

>>> v = sys.stdin.readline()
here is some text
>>> print(v)
here is some text
>>> v = sys.stdin.readline(13)
here is some text
[error text blah blah blah]```


what is supposed to happen is sys is supposed to save the first 13 characters (including spaces) of "here is some text".
if i do this in the actual IDLE, it does what is intended. but this does not happen in bpython. please fix this and any other commands that do not match up with the original python.
I am using Ubuntu 20.04.1, and the IDLE i mentioned is python 3.8 and bpython 0.18
Thank you.