old_contents: from astropy.table import Table
  import os
  
  
  class AuxService:
  
      renames = {}
      ignored_columns = []
      transforms = {}
      basename = 'AUX_SERVICE'
  
      def __init__(self, auxdir='/fact/aux'):
          self.auxdir = auxdir
          self.filename_template = os.path.join(
              self.auxdir, '{date:%Y}',  '{date:%m}', '{date:%d}',
              '{date:%Y%m%d}.' + self.basename + '.fits'
          )
  
      def read(self, date):
  
          filename = self.filename_template.format(date=date)
          df = Table.read(filename).to_pandas()
  
          df.drop(self.ignored_columns, axis=1, inplace=True)
          df.rename(columns=self.renames, inplace=True)
  
          for key, transform in self.transforms.items():
              df[key] = transform(df[key])
  
          return df
  
new_contents: from astropy.table import Table
  import os
  
  
  class AuxService:
  
      renames = {}
      ignored_columns = []
      transforms = {}
      basename = 'AUX_SERVICE'
  
      def __init__(self, auxdir='/fact/aux'):
          self.auxdir = auxdir
          self.filename_template = os.path.join(
              self.auxdir, '{date:%Y}',  '{date:%m}', '{date:%d}',
              '{date:%Y%m%d}.' + self.basename + '.fits'
          )
  
      def read_file(self, filename):
          df = Table.read(filename).to_pandas()
  
          df.drop(self.ignored_columns, axis=1, inplace=True)
          df.rename(columns=self.renames, inplace=True)
  
          for key, transform in self.transforms.items():
              df[key] = transform(df[key])
  
          return df
  
      def read_date(self, date):
  
          filename = self.filename_template.format(date=date)
          return self.read_file(filename)
  
subject: Add method to read from filename