### Information about bug
Hi ,
We just observed a recent issue with Payroll.… If you have statistical components with conditions set and those conditions are not fulfilled, the following error is thrown while trying to generate Salary Slips:
`Error in formula or condition: unsupported operand type(s) for +: 'NoneType' and 'NoneType'`
Kindly help fix asap
Thanks
### Module
other
### Version
ERPNext: v13.51.5 (version-13)
Frappe Framework: v13.57.1 (version-13)
### Installation method
None
### Relevant log output / Stack trace / Full Error Message.
```shell
'Traceback (most recent call last):
File "apps/erpnext/erpnext/payroll/doctype/salary_slip/salary_slip.py", line 736, in eval_condition_and_formula
amount = flt(frappe.safe_eval(formula, self.whitelisted_globals, data), d.precision("amount"))
File "apps/frappe/frappe/__init__.py", line 2119, in safe_eval
return eval(code, eval_globals, eval_locals)
File "<string>", line 1, in <module>
TypeError: unsupported operand type(s) for +: 'NoneType' and 'NoneType'
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "apps/frappe/frappe/utils/background_jobs.py", line 147, in execute_job
retval = method(**kwargs)
File "apps/erpnext/erpnext/payroll/doctype/payroll_entry/payroll_entry.py", line 761, in create_salary_slips_for_employees
ss.insert()
File "apps/frappe/frappe/model/document.py", line 263, in insert
self.run_before_save_methods()
File "apps/frappe/frappe/model/document.py", line 1054, in run_before_save_methods
self.run_method("validate")
File "apps/frappe/frappe/model/document.py", line 943, in run_method
out = Document.hook(fn)(self, *args, **kwargs)
File "apps/frappe/frappe/model/document.py", line 1264, in composer
return composed(self, method, *args, **kwargs)
File "apps/frappe/frappe/model/document.py", line 1246, in runner
add_to_return_value(self, fn(self, *args, **kwargs))
File "apps/frappe/frappe/model/document.py", line 940, in fn
return method_object(*args, **kwargs)
File "apps/erpnext/erpnext/payroll/doctype/salary_slip/salary_slip.py", line 77, in validate
self.get_emp_and_working_day_details()
File "apps/erpnext/erpnext/payroll/doctype/salary_slip/salary_slip.py", line 235, in get_emp_and_working_day_details
self.pull_sal_struct()
File "apps/erpnext/erpnext/payroll/doctype/salary_slip/salary_slip.py", line 307, in pull_sal_struct
make_salary_slip(self._salary_structure_doc.name, self)
File "apps/erpnext/erpnext/payroll/doctype/salary_structure/salary_structure.py", line 333, in make_salary_slip
doc = get_mapped_doc(
File "apps/frappe/frappe/model/mapper.py", line 149, in get_mapped_doc
postprocess(source_doc, target_doc)
File "apps/erpnext/erpnext/payroll/doctype/salary_structure/salary_structure.py", line 331, in postprocess
target.run_method("process_salary_structure", for_preview=for_preview)
File "apps/frappe/frappe/model/document.py", line 943, in run_method
out = Document.hook(fn)(self, *args, **kwargs)
File "apps/frappe/frappe/model/document.py", line 1264, in composer
return composed(self, method, *args, **kwargs)
File "apps/frappe/frappe/model/document.py", line 1246, in runner
add_to_return_value(self, fn(self, *args, **kwargs))
File "apps/frappe/frappe/model/document.py", line 940, in fn
return method_object(*args, **kwargs)
File "apps/erpnext/erpnext/payroll/doctype/salary_slip/salary_slip.py", line 1598, in process_salary_structure
self.calculate_net_pay()
File "apps/erpnext/erpnext/payroll/doctype/salary_slip/salary_slip.py", line 607, in calculate_net_pay
self.calculate_component_amounts("deductions")
File "apps/erpnext/erpnext/payroll/doctype/salary_slip/salary_slip.py", line 636, in calculate_component_amounts
self.add_structure_components(component_type)
File "apps/erpnext/erpnext/payroll/doctype/salary_slip/salary_slip.py", line 669, in add_structure_components
default_amount = self.eval_condition_and_formula(struct_row, default_data)
File "apps/erpnext/erpnext/payroll/doctype/salary_slip/salary_slip.py", line 750, in eval_condition_and_formula
frappe.throw(_("Error in formula or condition: {0}").format(e))
File "apps/frappe/frappe/__init__.py", line 504, in throw
msgprint(
File "apps/frappe/frappe/__init__.py", line 479, in msgprint
_raise_exception()
File "apps/frappe/frappe/__init__.py", line 434, in _raise_exception
raise raise_exception(msg)
frappe.exceptions.ValidationError: Error in formula or condition: unsupported operand type(s) for +: 'NoneType' and 'NoneType''
```