Blank importance objects can't be printed

[MicahGale]

Describe the bug

Importance is missing a default _tree and when str is called this leads to an AttributeError.

To Reproduce

A short code snippet of what you have ran. Please change or remove any specific values or anything that can't be public. For example:

problem = montepy.read_input("tests/inputs/test_importance.imcnp")
print(problem.cells._importance)

Error Message (if any)

If an error message was printed please include the entire stacktrace. If it includes any specific values please change or remove them. For example:

    print(self)
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

self = Importance: in_cell_block: False, set_in_cell_block False,
{}

    def __str__(self):
        if not self.in_cell_block and self._problem is None:
>           return " ".join(self.input_lines)
E           AttributeError: 'Importance' object has no attribute 'input_lines'

montepy/data_inputs/importance.py:165: AttributeError

MCNP input file snippet

see tests/inputs/test_importance.imcnp

Version

• Version 0.4.1

[kordusas]

Minimal snippet to reproduce the issue clearly:

from montepy.data_inputs.importance import Importance
imp = Importance()
print(imp)

[kordusas]

The more I look into this, the more I'm unsure about the intended behavior.

It's unclear to me why an Importance object should require an input_lines attribute in the first place. Could you clarify the expected behavior when an empty Importance object is printed? Should it raise a clear warning, return an empty representation, or something else?

I might have misunderstood the original bug description—some clarification would help here.
default _tree gets initialised in super().__init__(input, in_cell_block, key, value)

[MicahGale]

Good question. Let me take a sec to read my old mind.

[MicahGale]

So input_lines is a bit of a legacy from <0.2.0 There is still _input.input_lines, but this is really just and fast and dirty way to create __str__. Really we need to check if this is buggy code in CellModifier.__str__, and move printing just helpful state information from the object directly.