docstr: Add a value to the group.
docstr_tok: ["Add","a","value","to","the","group","."]
code: def addValue(self, value):
      """Add a value to the group."""
      raise NotImplementedError()
  
imports: import abc
  import datetime
  import six
  from pyalgotrade.utils import dt
  from pyalgotrade import bar
label_desc: Use image node_id 3 for calling the Grouper obj's underlying member method code with example usage: obj.addValue(value) without return types