Describe the bug
Hello, disappointed that it does not work with df which columns are based on MultiIndex.

To Reproduce
Steps to reproduce the behavior:

Run
df = pd.DataFrame(
{(1, 2): [1, 2, 3], (1, 3): [4, 5, 6]}
)
pygwalker.walk(df)

Error
53 for col in columns:
---> 54 col = col.replace("\", "-")
55 if column_map[col] == 0:
56 renamed_columns.append(col)

Expected behavior
Able to manage it.

Versions

• pygwalker version: 0.4.9.9
• python version : 3.12