AttributeError: 'float' object has no attribute 'quantize' using django-firebird - django

Question

I'm using:
Django 2.2.24,
django-firebird 2.2a1,
fdb 2.02,
my model:
class MyModel(models.Model):
...
total = models.DecimalField(max_digits=10, decimal_places=2, null=True)
...
When i run a simple query:
ml = MyModel.objects.values('id', 'total').last()
I got this error:
AttributeError: 'float' object has no attribute 'quantize'
I guess the issue is with converters from firebird/operations.py
Full traceback:
~/.pyenv/versions/crm-nov21/lib/python3.7/site-packages/django/db/models/query.py in last(self)
656 def last(self):
657 """Return the last object of a query or None if no match is found."""
--> 658 for obj in (self.reverse() if self.ordered else self.order_by('-pk'))[:1]:
659 return obj
660
~/.pyenv/versions/crm-nov21/lib/python3.7/site-packages/django/db/models/query.py in __iter__(self)
272 - Responsible for turning the rows into model objects.
273 """
--> 274 self._fetch_all()
275 return iter(self._result_cache)
276
~/.pyenv/versions/crm-nov21/lib/python3.7/site-packages/django/db/models/query.py in _fetch_all(self)
1240 def _fetch_all(self):
1241 if self._result_cache is None:
-> 1242 self._result_cache = list(self._iterable_class(self))
1243 if self._prefetch_related_lookups and not self._prefetch_done:
1244 self._prefetch_related_objects()
~/.pyenv/versions/crm-nov21/lib/python3.7/site-packages/django/db/models/query.py in __iter__(self)
111 ]
112 indexes = range(len(names))
--> 113 for row in compiler.results_iter(chunked_fetch=self.chunked_fetch, chunk_size=self.chunk_size):
114 yield {names[i]: row[i] for i in indexes}
115
~/.pyenv/versions/crm-nov21/lib/python3.7/site-packages/django/db/models/sql/compiler.py in apply_converters(self, rows, converters)
1084 value = row[pos]
1085 for converter in convs:
-> 1086 value = converter(value, expression, connection)
1087 row[pos] = value
1088 yield row
~/.pyenv/versions/crm-nov21/lib/python3.7/site-packages/firebird/operations.py in convert_decimalfield_value(self, value, expression, connection, context)
304 field = expression.field
305
--> 306 val = utils.format_number(value, field.max_digits, field.decimal_places)
307 value = decimal.Decimal.from_float(float(val))
308 return value
~/.pyenv/versions/crm-nov21/lib/python3.7/site-packages/django/db/backends/utils.py in format_number(value, max_digits, decimal_places)
236 context.prec = max_digits
237 if decimal_places is not None:
--> 238 value = value.quantize(decimal.Decimal(1).scaleb(-decimal_places), context=context)
239 else:
240 context.traps[decimal.Rounded] = 1
AttributeError: 'float' object has no attribute 'quantize'
could someone help me please ?