class_docstr: Base class for cohort definitions. In order to implement a new cohort, you should
  subclass this class and implement :meth:`population` and :meth:`data_split`.
docstr: Return the population as a pandas dataframe with an index named PERSON_ID.
  This dataframe will be left joined on the sentences, so any additional columns
  will be included in sentence data of the corpus. Should atleast include BIRTHDAY
  and GENDER (M/F).
docstr_tok: ["Return","the","population","as","a","pandas","dataframe","with","an","index","named","PERSON_ID",".","This","dataframe","will","be","left","joined","on","the","sentences",",","so","any","additional","columns","will","be","included","in","sentence","data","of","the","corpus",".","Should","atleast","include","BIRTHDAY","and","GENDER","(","M\/F",")","."]
code: def population(self) -> pd.DataFrame:
      """
      Return the population as a pandas dataframe with an index named PERSON_ID.
      This dataframe will be left joined on the sentences, so any additional columns
      will be included in sentence data of the corpus. Should atleast include BIRTHDAY
      and GENDER (M/F).
      """
      raise NotImplementedError
  
file_path: life2vec/src/data_new/populations/base.py
imports: from dataclasses import dataclass
  import numpy
  import pandas
label_desc: Use image node_id 1 for calling the Population obj's underlying member method code with example usage: obj.population() without return types