code: def set_default(self, field):
          
  
          # Record specification fields
          if field in RECORD_SPECS.index:
              # Return if no default to set, or if the field is already
              # present.
              if RECORD_SPECS.loc[field, 'write_default'] is None or getattr(self, field) is not None:
                  return
              setattr(self, field, RECORD_SPECS.loc[field, 'write_default'])
  
          # Signal specification fields
          # Setting entire list default, not filling in blanks in lists.
          elif field in SIGNAL_SPECS.index:
  
              # Specific dynamic case
              if field == 'file_name' and self.file_name is None:
                  self.file_name = self.n_sig * [self.record_name + '.dat']
                  return
  
              item = getattr(self, field)
  
              # Return if no default to set, or if the field is already
              # present.
              if SIGNAL_SPECS.loc[field, 'write_default'] is None or item is not None:
                  return
  
              # Set more specific defaults if possible
              if field == 'adc_res' and self.fmt is not None:
                  self.adc_res = _signal._fmt_res(self.fmt)
                  return
  
              setattr(self, field,
                     [SIGNAL_SPECS.loc[field, 'write_default']] * self.n_sig)
docs: Set the object's attribute to its default value if it is missing
          and there is a default.
  
          Not responsible for initializing the
          attribute. That is done by the constructor.