code: def sequence_of(types):
      def validator(_, attrib, value):
          assert all(isinstance(x, types) for x in value), attrib.name
  
      return and_(sequence, validator)
  
imports: import attr
  from attr.validators import and_, instance_of, optional
  from six import string_types
label_desc: Use image node_id 1 for calling a global function with example usage: sequence_of(types) and returns: and_