code: def get_intensity_col(data):
      
      # possible intensity columns
      intlist = ['magn_moment', 'magn_volume', 'magn_mass','magn_uncal']
      # intensity columns that are in the data
      int_meths = [col_name for col_name in data.columns if col_name in intlist]
      # drop fully null columns
      data.dropna(axis='columns', how='all')
      # ignore columns with only blank values (including "")
      for col_name in int_meths[:]:
          if not data[col_name].any():
              int_meths.remove(col_name)
      if len(int_meths):
          if 'magn_moment' in int_meths:
              return 'magn_moment'
          return int_meths[0]
      return ""
docs: Check measurement dataframe for intensity columns 'magn_moment', 'magn_volume', 'magn_mass','magn_uncal'.
      Return the first intensity column that is in the dataframe AND has data.
  
      Parameters
      ----------
      data : pandas DataFrame
  
      Returns
      ---------
      str
          intensity method column or ""