Example:
```
import ifcopenshell
ifc_file = ifcopenshell.file(schema="IFC2X3")
# ifc_file.begin_transaction()
wall = ifc_file.createIfcWall()
wall.Identification = "25"
# Before:
# Traceback (most recent call last):
# File "test.py", line 4, in <module>
# wall.Identification = "25"
# ^^^^^^^^^^^^^^^^^^^
# File "\ifcopenshell\entity_instance.py", line 279, in __setattr__
# self[index] = value
# ~~~~^^^^^^^
# File "\ifcopenshell\entity_instance.py", line 293, in __setitem__
# method = self.method_list[idx]
# ~~~~~~~~~~~~~~~~^^^^^
# IndexError: list index out of range
# or this (if file had a transaction going)
# File "\ifcopenshell\entity_instance.py", line 279, in __setattr__
# self[index] = value
# ~~~~^^^^^^^
# File "\ifcopenshell\entity_instance.py", line 288, in __setitem__
# self.wrapped_data.file.transaction.store_edit(self, idx, value)
# File "\ifcopenshell\file.py", line 101, in store_edit
# "old": self.serialise_value(element, element[index]),
# ~~~~~~~^^^^^^^
# File "\ifcopenshell\entity_instance.py", line 283, in __getitem__
# raise IndexError("Attribute index {} out of range for instance of type {}".format(key, self.is_a()))
# IndexError: Attribute index 4294967295 out of range for instance of type IfcWall
# After:
# Traceback (most recent call last):
# File "test.py", line 4, in <module>
# wall.Identification = "25"
# ^^^^^^^^^^^^^^^^^^^
# File "ifcopenshell\entity_instance.py", line 283, in __setattr__
# raise AttributeError(
# AttributeError: entity instance of type 'IFC2X3.IfcWall' has no attribute 'Identification'
```
ifcpatch ConvertLengthUnit - change used units from plural to singular names, to make it consistent across the api
more test coverage - test converting to more units and back from them
the error is below, not sure how I haven't noticed it before 🤔
assert subject.format('imperial_length(1, 1)') == "1'"
> raise VisitError(tree.data, tree, e)
E lark.exceptions.VisitError: Error trying to process rule "imperial_length":
E
E cannot access local variable 'output_unit' where it is not associated with a value