Hello odooers,

i'm trying to convert the total amount of the sale order to letter using to the app studio.

I created a text  computed field called letters and here's the code i used to get the amount in letter :

for rec in self:
rec['x_studio_letters']=rec.currency_id.amount_to_text(rec.amount_total)

 i put  amount_total,x_studio_letters in dependencies

the problem is i'm getting this bug everytime i try to create a new quotation :

Traceback (most recent call last):
  File "/home/odoo/src/odoo/14.0/odoo/http.py", line 640, in _handle_exception
    return super(JsonRequest, self)._handle_exception(exception)
  File "/home/odoo/src/odoo/14.0/odoo/http.py", line 316, in _handle_exception
    raise exception.with_traceback(None) from new_cause
ValueError: : "Expected singleton: res.currency()" while evaluating
"for rec in self:\n  rec['x_studio_letters']=rec.currency_id.amount_to_text(rec.amount_total)"