code: def build(self):
      schema = {}
      if issubclass(self.type, six.string_types):
          obj_type = "string"
      elif issubclass(self.type, bool):
          obj_type = "boolean"
      elif issubclass(self.type, int):
          obj_type = "number"
      elif issubclass(self.type, float):
          obj_type = "number"
      else:
          raise errors.FieldNotSupported(
              "Can't specify value schema!", self.type
          )
  
      if self.nullable:
          obj_type = [obj_type, "null"]
      schema["type"] = obj_type
  
      if self.has_default:
          schema["default"] = self.default
  
      return schema
  
imports: from __future__ import absolute_import
  from collections import defaultdict
  import six
  from .None import errors
  from .fields import NotSet
label_desc: Use image node_id 2 for calling the PrimitiveBuilder obj's underlying member method code with example usage: obj.build() and returns: schema