"""API layer — Workbook/Worksheet wrappers and supporting modules."""


def write_op(fn):
    """Mark a method as a write operation.

    The agent-side code analyzer maintains a list of write-op method names
    that must stay in sync with methods tagged here.  The sync test
    (excel-code-analyzer-sync.test.ts) parses the Python source for
    ``@write_op`` lines and verifies the TS list matches.

    Zero-overhead at runtime — just returns the function unchanged.
    """
    return fn
