class_docstr: Restrictions based on a security list.
  
  Parameters
  ----------
  restrictions : zipline.utils.security_list.SecurityList
      The restrictions defined by a SecurityList
class_docstr_tok: ["Restrictions","based","on","a","security","list",".","Parameters","--","--","--","--","--","restrictions",":","zipline.utils.security_list.SecurityList","The","restrictions","defined","by","a","SecurityList"]
code: def __init__(self, security_list_by_dt):
      self.current_securities = security_list_by_dt.current_securities
  
imports: import abc
  from numpy import vectorize
  from functools import partial, reduce
  import operator
  import pandas
  from six import with_metaclass, iteritems
  from collections import namedtuple
  from toolz import groupby
  from zipline.utils.enum import enum
  from zipline.utils.numpy_utils import vectorized_is_element
  from zipline.assets import Asset
label_desc: Use image node_id 1 to create a new SecurityListRestrictions object from inherited base classes: Restrictions with example: obj = SecurityListRestrictions(security_list_by_dt)