Django model class

model.py

class Model(metaclass=ModelBase):

    def __init__(self, *args, **kwargs):
      """
      initializes an instance of this data model
      """

    @classmethod
    def from_db(cls, db, field_names, values):
    
    def __repr__(self):
        return '<%s: %s>' % (self.__class__.__name__, self)

    def __str__(self):
        return '%s object (%s)' % (self.__class__.__name__, self.pk)

    def __eq__(self, other):
        if not isinstance(other, Model):
            return False
        if self._meta.concrete_model != other._meta.concrete_model:
            return False
        my_pk = self.pk
        if my_pk is None:
            return self is other
        return my_pk == other.pk

    def __hash__(self):
        if self.pk is None:
            raise TypeError("Model instances without primary key value are unhashable")
        return hash(self.pk)

    def __reduce__(self):
        data = self.__getstate__()
        data[DJANGO_VERSION_PICKLE_KEY] = get_version()
        class_id = self._meta.app_label, self._meta.object_name
        return model_unpickle, (class_id,), data

    def __getstate__(self):
        """Hook to allow choosing the attributes to pickle."""
        return self.__dict__

    def __setstate__(self, state):
        msg = None
        pickled_version = state.get(DJANGO_VERSION_PICKLE_KEY)
        if pickled_version:
            current_version = get_version()
            if current_version != pickled_version:
                msg = (
                    "Pickled model instance's Django version %s does not match "
                    "the current version %s." % (pickled_version, current_version)
                )
        else:
            msg = "Pickled model instance's Django version is not specified."

        if msg:
            warnings.warn(msg, RuntimeWarning, stacklevel=2)

        self.__dict__.update(state)

    def _get_pk_val(self, meta=None):
        meta = meta or self._meta
        return getattr(self, meta.pk.attname)

    def _set_pk_val(self, value):
        return setattr(self, self._meta.pk.attname, value)

    pk = property(_get_pk_val, _set_pk_val)

    def get_deferred_fields(self):
        """
        Return a set containing names of deferred fields for this instance.
        """
        
    def refresh_from_db(self, using=None, fields=None):
        """
        Reload field values from the database.
        """
        
    def serializable_value(self, field_name):
        """
        Return the value of the field name for this instance. If the field is
        a foreign key, return the id value instead of the object. If there's
        no Field object with this name on the model, return the model
        attribute's value.

        Used to serialize a field's value (in the serializer, or form output,
        for example). Normally, you would just access the attribute directly
        and not use this method.
        """
        
    def save(self, force_insert=False, force_update=False, using=None,
             update_fields=None):
        """
        Save the current instance. Override this in a subclass if you want to
        control the saving process.

        The 'force_insert' and 'force_update' parameters can be used to insist
        that the "save" must be an SQL insert or update (or equivalent for
        non-SQL backends), respectively. Normally, they should not be set.
        """
        
    def save_base(self, raw=False, force_insert=False,
                  force_update=False, using=None, update_fields=None):
        """
        Handle the parts of saving which should be done only once per save,
        yet need to be done in raw saves, too. This includes some sanity
        checks and signal sending.

        The 'raw' argument is telling save_base not to save any parent
        models and not to do any changes to the values before save. This
        is used by fixture loading.
        """
        
    def _save_parents(self, cls, using, update_fields):
        """Save all the parents of cls using values from self."""
        ...

    def _save_table(self, raw=False, cls=None, force_insert=False,
                    force_update=False, using=None, update_fields=None):
        """
        Do the heavy-lifting involved in saving. Update or insert the data
        for a single table.
        """
        ...

    def _do_update(self, base_qs, using, pk_val, values, update_fields, forced_update):
        """
        Try to update the model. Return True if the model was updated (if an
        update query was done and a matching row was found in the DB).
        """
        ...

    def _do_insert(self, manager, using, fields, returning_fields, raw):
        """
        Do an INSERT. If returning_fields is defined then this method should
        return the newly created data for the model.
        """

    def delete(self, using=None, keep_parents=False):
      ...
      
    def _get_FIELD_display(self, field):
      ...