Hi, I created a custom module in Odoo, and added a few custom models that work successfully. But I've started having some issues when I tried to add a custom method to one of them.

I have this model named "azienda.py" (which, in English, would have been "company.py"), in which I've added this field.Char named "codice_ateco" (is a code that in Italy is given to each company to address its category, such as manufactoring, mining...). This code should have a structure of this kind: LETTER . NUMBER - NUMBER . NUMBER - NUMBER . NUMBER - NUMBER, but I didn't know how to give it this structure, so I just created a field.Char giving it size=7. 

class Azienda(models.Model):
  _name="piani_formazione.azienda"

  [...]  codice_ateco = fields.Char(string="Codice ATECO", size=7, required=True) [...]

From this point, I should create a new field.Selection called "categoria_rischio" ("risk_category") which could assume the valued "basso", "medio" or "alto" (in English, they would be "low", "medium" and "high") based on the value of the first letter of the "codice_ATECO". 

  [...] categoria_rischio = fields.Selection([('basso','Basso'),('medio','Medio'),
     ('alto','Alto'),('indefinite','error in codice ATECO definition')], compute="_compute_categoria_rischio", store=True, 
     string="Categoria di rischio")

And I defined the method as follows (at the end of the azienda.py file)

@api.depends("codice_ateco")
def _compute_categoria_rischio(self): 
  if ('B' or 'C' or 'D' or 'E' or 'F' or 'Q') in str(self.codice_ateco):            
    self.categoria_rischio = 'alto'        
  elif ('A' or 'H' or 'O' or 'P') in str(self.codice_ateco):            
    self.categoria_rischio = 'medio'        
  elif ('G' or 'I' or 'J' or 'K' or 'L' or 'M' or 'N' or 'R' or 'S' or 'T' or 'U') in str(self.codice_ateco):            
    self.categoria_rischio = 'basso'        
  else:            
    self.categoria_rischio = 'indefinite'

Unfortunately, it works only for "A","B" and "G"; all the values after the ors give back the wrong value of the categoria_rischio, the 'error in codice ATECO definition' one (that I setted in the "else" option). 

EDITED: ups, I indented it wrong: I fixed it and modified the question according to the new issue: my question remain unresolved

EDITED 2: I used the or between the conditions and now the method works!