docs: def has_platform(self, platform):
          """
          Check whether the given platform identifier is available for this
          digest.
  
          Args:
              platform (str or dict): A string using the ``os[/arch[/variant]]``
                  format, or a platform dictionary.
  
          Returns:
              (bool): ``True`` if the platform is recognized as available,
              ``False`` otherwise.
  
          Raises:
              :py:class:`docker.errors.InvalidArgument`
                  If the platform argument is not a valid descriptor.
          """
          if platform and not isinstance(platform, dict):
              parts = platform.split('/')
              if len(parts) > 3 or len(parts) < 1:
                  raise InvalidArgument(
                      '"{0}" is not a valid platform descriptor'.format(platform)
                  )
              platform = {'os': parts[0]}
              if len(parts) > 2:
                  platform['variant'] = parts[2]
              if len(parts) > 1:
                  platform['architecture'] = parts[1]
          return normalize_platform(
              platform, self.client.version()
          ) in self.attrs['Platforms']