adding a new @classmethod to an existing class #1173

I have a python programming issue which I have not solved.

In python3, using 'from opencadd.structure.core import Structure'

defines the class Structure. The section of the Structure code that I need to modify is

@classmethod
@redo.retriable(attempts=10, sleeptime=2)
def from_pdbid(cls, pdbid):
    import mmtf

    return cls(mmtf.fetch(pdbid))

where I would like to include

# New method for CIF files
@classmethod
def from_cif(cls, filepath: str):
    """
    Create a Structure object from a local CIF file.
    """
    parser = MMCIFParser()
    structure_data = parser.get_structure("cif_file", filepath)
    # ... (processing to build Volkamer Structure object)
    return cls(atoms, residues, bonds)

This will skip trying to execute mmtf.fetch (which will timeout because pdb is no longer available for mmtf.fetch).
Instead using Structure.from_cif will avoid this issue and retrieve the file.

So far, I have not been able to do this successfully. Many blogs offer suggestions about adding a classmethod,
but I have failed and am asking for help from python exports.

Thanks in advance,
David
Fortran, R, Matlab, C, AWK, Perl, no Python