code: def to_csv(objects, filename, digits=5, warnings=True):
      
  
      if not isinstance(objects, list):
          objects = [objects]
  
      data = [flatten(obj) for obj in objects]
      all_keys = [d for datum in data for d in datum.keys()]
      field_names = sorted(set(all_keys), key=lambda x: all_keys.index(x))
  
      with open(filename, 'w') as f:
          w = csv.writer(f)
          w.writerow(field_names)
  
          def make_repr(item):
              if item is None:
                  return None
              elif isinstance(item, float):
                  return repr(round(item, digits))
              else:
                  return str(item)
  
          for row in data:
              row = dict((k, make_repr(v)) for k, v in row.items())
              w.writerow([make_repr(row.get(k, None)) for k in field_names])
  
      if warnings:
          print("Successfully exported {} object(s) to {}".format(len(objects),
                filename))
docs: Export the flatten indicators of one or several users to CSV.
  
      Parameters
      ----------
      objects : list
          List of objects to be exported.
      filename : string
          File to export to.
      digits : int
          Precision of floats.
  
      Examples
      --------
      This function can be used to export the results of
      :meth`bandicoot.utils.all`.
      >>> U_1 = bc.User()
      >>> U_2 = bc.User()
      >>> bc.to_csv([bc.utils.all(U_1), bc.utils.all(U_2)], 'results_1_2.csv')
  
      If you only have one object, you can simply pass it as argument:
      >>> bc.to_csv(bc.utils.all(U_1), 'results_1.csv')