code: def check_time(value):
      
      try:
          h, m = value.split(':')
          h = int(h)
          m = int(m)
          if h >= 24 or h < 0:
              raise ValueError
          if m >= 60 or m < 0:
              raise ValueError
      except ValueError:
          raise TimeDefinitionError("Invalid definition of time %r" % value)
docs: check that it's a value like 03:45 or 1:1