Impacted versions:10

Steps to reproduce:
Following the code in https://www.odoo.com/documentation/10.0/api_integration.html both in a fresh install and against 'https://demo.odoo.com/start' trows a type error

Current behavior:
Now I get an error when executing:

```
ids = models.execute_kw(db, uid, password,  'res.partner', 'search',
    [[['is_company', '=', True], ['customer', '=', True]]],
    {'limit': 1})
[record] = models.execute_kw(db, uid, password,
    'res.partner', 'read', [ids])
# count the number of fields fetched by default
len(record)
```

In particular it seems to be a type error (cannot marshal class odoo.tools.float_utils.float_precision)

Expected behavior:
I would expect it to behave as in the documentation

openerp/fields.py
type = 'html'
    _slots = {
        'sanitize': True,               
        'strip_style': False,           
        'strip_classes': False,         
    }
    def _setup_attrs(self, model, name):
        super(Html, self)._setup_attrs(model, name)
        
        if self.translate and not callable(self.translate) and self.sanitize:
            self.translate = html_translate
    _column_sanitize = property(attrgetter('sanitize'))
    _related_sanitize = property(attrgetter('sanitize'))
    _description_sanitize = property(attrgetter('sanitize'))
    _column_strip_style = property(attrgetter('strip_style'))
    _related_strip_style = property(attrgetter('strip_style'))
    _description_strip_style = property(attrgetter('strip_style'))
    _column_strip_classes = property(attrgetter('strip_classes'))
    _related_strip_classes = property(attrgetter('strip_classes'))
    _description_strip_classes = property(attrgetter('strip_classes'))
    def convert_to_cache(self, value, record, validate=True):
        if value is None or value is False:
            return False
        if validate and self.sanitize:
            return html_sanitize(value, silent=True, strict=True, strip_style=self.strip_style, strip_classes=self.strip_classes)
        return value
class Date(Field):