Error when trying to import invoices

Hello,
I am unable to upload any Sales Invoice.

        Traceback (most recent call last):
          File "/home/frappe/frappe-bench/apps/frappe/frappe/core/doctype/data_import/importer.py", line 392, in upload
            doc = frappe.get_doc(doc)
          File "/home/frappe/frappe-bench/apps/frappe/frappe/__init__.py", line 638, in get_doc
            return frappe.model.document.get_doc(*args, **kwargs)
          File "/home/frappe/frappe-bench/apps/frappe/frappe/model/document.py", line 68, in get_doc
            return controller(*args, **kwargs)
        TypeError: __init__() keywords must be strings