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
default ``False`` on computed fields)
        :param compute_sudo: whether the field should be recomputed as superuser
            to bypass access rights (boolean, by default ``False``)
        The methods given for ``compute``, ``inverse`` and ``search`` are model
        methods. Their signature is shown in the following example::
            upper = fields.Char(compute='_compute_upper',
                                inverse='_inverse_upper',
                                search='_search_upper')
            @api.depends('name')
            def _compute_upper(self):
                for rec in self:
                    rec.upper = rec.name.upper() if rec.name else False
            def _inverse_upper(self):
                for rec in self:
                    rec.name = rec.upper.lower() if rec.upper else False
            def _search_upper(self, operator, value):
                if operator == 'like':
                    operator = 'ilike'
                return [('name', operator, value)]
        The compute method has to assign the field on all records of the invoked
        recordset. The decorator :meth:`openerp.api.depends` must be applied on
        the compute method to specify the field dependencies; those dependencies
        are used to determine when to recompute the field; recomputation is
        automatic and guarantees cache/database consistency. Note that the same
        method can be used for several fields, you simply have to assign all the
        given fields in the method; the method will be invoked once for all
        those fields.
        By default, a computed field is not stored to the database, and is
        computed on-the-fly. Adding the attribute ``store=True`` will store the
        field's values in the database. The advantage of a stored field is that