code: def _read_regenie_df(file, trait, num_snps):
      df = pd.read_table(file, sep=r"\s+").astype({"ID": "str"})
      df = df[df["GENPOS"] <= num_snps]
      df["phenotype"] = trait
      return df
  
file_path: glow/python/glow/gwas/tests/functions.py
imports: import glow.functions
  import numpy
  import pandas
  from pandas.testing import assert_frame_equal
label_desc: Use image node_id 3 for calling a global function with example usage: _read_regenie_df(file, trait, num_snps) and returns: df