code: def _str_datetime_now(self, x=None):
          
          if (x == 'now'):
              # Now, this is wht datetime_to_str() with no arg gives
              return(datetime_to_str())
          try:
              # Test for number
              junk = x + 0.0
              return datetime_to_str(x)
          except TypeError:
              # Didn't look like a number, treat as string
              return x
docs: Return datetime string for use with time attributes.
  
          Handling depends on input:
            'now'   - returns datetime for now
            number  - assume datetime values, generate string
            other   - no change, return same value