title: Design a field value verification (not odoo.api.constrains validation)
body: <p>Class Diagram:</p>
  <pre><code>   ,-------------------.    
     | question_request  |   
     |-------------------|    
     | +Char Name        |    
     | +Char LastName    |    
     | +Integer Age      |    
     | +Text Description |    
     |-------------------|    
     `-------------------'
  </code></pre>
  <p>Code</p>
  <pre><code>from odoo import models, fields, api
  
    class Request(models.Model):
      _name = 'test.request'
      _description = &quot;Request&quot;
      
      name = fields.Char(string=&quot;Name&quot;, required=True)
      last_name = fields.Char(string=&quot;Last Name&quot;, required=True)
      age = fields.Integer(string=&quot;Age&quot;, required=True)
      description = fields.Text() 
  </code></pre>
  <p>Goal:</p>
  <p>Feature for field's value manual verification by users.</p>
  <p>Ex: Customer send a request with field's values as follow:​</p>
  <pre><code>Name:     &quot;Peterrrrrrrrrr&quot;
  LastName: &quot;Smith&quot;
  Age:      150
  </code></pre>
  <p>An employee user would be able to inform to the customer about the wrong values as follows:</p>
  <pre><code>Name:     State=Invalid, Comment=&quot;Probably Typo error&quot;
  LastName: State=Valid
  Age:      State=Invalid, Comment=&quot;Confirm real age&quot;
  </code></pre>
  <p>It's not a feature about value validation (odoo.api.constrains(*args)), but about manual values verification by an user (abcde is a <strong>valid</strong> value for the <em>name</em> field, but an user need to <strong>confirm</strong> or <strong>verify</strong> that).</p>
  <p>The first idea was to use an extra field for verification and another extra field for the comment</p>
  <pre><code>from odoo import models, fields, api
  
    class Request(models.Model):
      _name = 'test.request'
      _description = &quot;Request&quot;
      
      name = fields.Char(string=&quot;Name&quot;, required=True)
      last_name = fields.Char(string=&quot;Last Name&quot;, required=True)
      age = fields.Integer(string=&quot;Age&quot;, required=True)
      description = fields.Text() 
      
      # fields for verification
      name_verification = fields.Selection([
        ('valid', 'Valid'),
        ('invalid', 'Invalid'),
        ('notverified', 'Not verified')
      ], default=&quot;notverified&quot;)
      name_verification_comment = fields.Text()
      
  </code></pre>
  <p>​
  But this is not a good approach because the need of implementing the 'field_value_verification' for each field and each model which need the verification feature.
  So I thought to store the 'field_value_verification' in the 'FieldsVerification' related model as follows:</p>
  <pre><code>from odoo import models, fields, api
  
    class Request(models.Model):
      _name = 'test.request'
      _description = &quot;Request&quot;
      
      name = fields.Char(string=&quot;Name&quot;, required=True)
      last_name = fields.Char(string=&quot;Last Name&quot;, required=True)
      age = fields.Integer(string=&quot;Age&quot;, required=True)
      description = fields.Text() 
      fueld_verification_ids = ???
      
    class FieldsVerification(models.Model): 
      _name = 'test.fields_verification'
      _description = &quot;Verification&quot;
      
      class_name = fields.Char(strng=&quot;Class&quot;)
      record_id = ???
      field_name = fields.Char(string=&quot;Field&quot;)
      status = fields .Selection([
        ('valid', 'Valid'),
        ('invalid', 'Invalid'),
        ('notverified', 'Not verified')
      ], default=&quot;notverified&quot;)
  </code></pre>
  <p>​
  Just right here I got stuck, so I thought to ask to the community.
  Thanks in advance</p>