Step command does not work since robotframework 4.x

[xyb]

robotframework-debuglibrary's step command does not work with robotframework 4.x and 5.x. The unit test results also reveal this problem.

Steps to reproduce the problem:

# checkout robotframework-debuglibrary
$ python setup.py develop
# install rf 4.x
$ pip install -U "robotframework<5"
# step command does not work
$ python DebugLibrary/shell.py tests/step.robot
==============================================================================
Step & Robot-Debug-Ua7Hv44X
==============================================================================
Step & Robot-Debug-Ua7Hv44X.Step
==============================================================================
test1
>>>>> Enter interactive shell
Only accepted plain text format keyword separated with two or more spaces.
Type "help" for more information.
> l
Please run `step` or `next` command first.
> s
.=> BuiltIn.Log To Console  working
> l
> s
working
.=> @{list} = BuiltIn.Create List  hello  world
> l
> s
test1                                                                 | PASS |
------------------------------------------------------------------------------
test2                                                                 => BuiltIn.Log To Console  another test case
> l
> s
another test case
.=> BuiltIn.Log To Console  end
> l
> s
end
test2                                                                 | PASS |
------------------------------------------------------------------------------
Step & Robot-Debug-Ua7Hv44X.Step                                      | PASS |
2 tests, 2 passed, 0 failed
==============================================================================
Step & Robot-Debug-Ua7Hv44X.Robot-Debug-Ua7Hv44X
==============================================================================
RFDEBUG REPL                                                          => DebugLibrary.Debug
> l
> s
> s
RFDEBUG REPL                                                          | PASS |
------------------------------------------------------------------------------
Step & Robot-Debug-Ua7Hv44X.Robot-Debug-Ua7Hv44X                      | PASS |
1 test, 1 passed, 0 failed
==============================================================================
Step & Robot-Debug-Ua7Hv44X                                           | PASS |
3 tests, 3 passed, 0 failed
==============================================================================
Output:  /Users/xyb/Projects/debuglibrary/output.xml
Log:     /Users/xyb/Projects/debuglibrary/log.html
Report:  /Users/xyb/Projects/debuglibrary/report.html

# install rf 3.x
$ pip install -U "robotframework<4"
# step command works
$ python DebugLibrary/shell.py tests/step.robot
==============================================================================
Step & Robot-Debug-Liqmv00V
==============================================================================
Step & Robot-Debug-Liqmv00V.Step
==============================================================================
test1
>>>>> Enter interactive shell
Only accepted plain text format keyword separated with two or more spaces.
Type "help" for more information.
> l
Please run `step` or `next` command first.
> s
.> /Users/xyb/Projects/debuglibrary/tests/step.robot(7)
-> log to console  working
=> BuiltIn.Log To Console  working
> l
  2   	Library  DebugLibrary
  3
  4   	** test case **
  5   	test1
  6   	    debug
  7 ->	    log to console  working
  8   	    @{list} =  Create List    hello    world
  9
 10   	test2
 11   	    log to console  another test case
 12   	    log to console  end
> s
working
.> /Users/xyb/Projects/debuglibrary/tests/step.robot(8)
-> @{list} =  Create List    hello    world
=> @{list} = BuiltIn.Create List  hello  world
> s
test1                                                                 | PASS |
------------------------------------------------------------------------------
test2                                                                 > /Users/xyb/Projects/debuglibrary/tests/step.robot(11)
-> log to console  another test case
=> BuiltIn.Log To Console  another test case
> s
another test case
.> /Users/xyb/Projects/debuglibrary/tests/step.robot(12)
-> log to console  end
=> BuiltIn.Log To Console  end
> s
end
test2                                                                 | PASS |
------------------------------------------------------------------------------
Step & Robot-Debug-Liqmv00V.Step                                      | PASS |
2 critical tests, 2 passed, 0 failed
2 tests total, 2 passed, 0 failed
==============================================================================
Step & Robot-Debug-Liqmv00V.Robot-Debug-Liqmv00V
==============================================================================
RFDEBUG REPL                                                          > /var/folders/t1/yzgk5r1x0w33lvm1x3n807k80000gn/T/robot-debug-liqmv00v.robot(6)
-> debug
=> DebugLibrary.Debug
> s
> s
RFDEBUG REPL                                                          | PASS |
------------------------------------------------------------------------------
Step & Robot-Debug-Liqmv00V.Robot-Debug-Liqmv00V                      | PASS |
1 critical test, 1 passed, 0 failed
1 test total, 1 passed, 0 failed
==============================================================================
Step & Robot-Debug-Liqmv00V                                           | PASS |
3 critical tests, 3 passed, 0 failed
3 tests total, 3 passed, 0 failed
==============================================================================
Output:  /Users/xyb/Projects/debuglibrary/output.xml
Log:     /Users/xyb/Projects/debuglibrary/log.html
Report:  /Users/xyb/Projects/debuglibrary/report.html

[xyb]

fixed in fa12110