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
""" High-level objects for fields. """
from collections import OrderedDict, defaultdict
from datetime import date, datetime
from functools import partial
from operator import attrgetter
from types import NoneType
import logging
import pytz
import xmlrpclib
from openerp.sql_db import LazyCursor
from openerp.tools import float_precision, float_round, frozendict, html_sanitize, ustr, OrderedSet
from openerp.tools import DEFAULT_SERVER_DATE_FORMAT as DATE_FORMAT
from openerp.tools import DEFAULT_SERVER_DATETIME_FORMAT as DATETIME_FORMAT
from openerp.tools.translate import html_translate
DATE_LENGTH = len(date.today().strftime(DATE_FORMAT))
DATETIME_LENGTH = len(datetime.now().strftime(DATETIME_FORMAT))
EMPTY_DICT = frozendict()
_logger = logging.getLogger(__name__)
Default = object()                      
class SpecialValue(object):