Version-Release number of selected component:
python3-idle-3.6.6-1.fc28

Additional info:
reporter:       libreport-2.9.6
cmdline:        /usr/bin/python3.6 /usr/bin/idle3
crash_function: write
exception_type: AttributeError
executable:     /usr/bin/idle3
interpreter:    python3-3.6.6-1.fc28.x86_64
kernel:         4.18.14-200.fc28.x86_64
runlevel:       N 5
type:           Python3
uid:            1000

Truncated backtrace:
pyshell.py:1295:write:AttributeError: 'NoneType' object has no attribute 'mark_gravity'

Traceback (most recent call last):
  File "/usr/bin/idle3", line 5, in <module>
    main()
  File "/usr/lib64/python3.6/idlelib/pyshell.py", line 1506, in main
    shell = flist.open_shell()
  File "/usr/lib64/python3.6/idlelib/pyshell.py", line 327, in open_shell
    if not self.pyshell.begin():
  File "/usr/lib64/python3.6/idlelib/pyshell.py", line 1055, in begin
    (sys.version, sys.platform, self.COPYRIGHT, nosub))
  File "/usr/lib64/python3.6/idlelib/pyshell.py", line 1295, in write
    self.text.mark_gravity("iomark", "left")
AttributeError: 'NoneType' object has no attribute 'mark_gravity'

Local variables in innermost frame:
count: 160
tags: ()
s: 'Python 3.6.6 (default, Jul 19 2018, 14:25:17) \n[GCC 8.1.1 20180712 (Red Hat 8.1.1-5)] on linux\nType "copyright", "credits" or "license()" for more information.\n'
self: <idlelib.pyshell.PyShell object at 0x7f37490c8588>