code: def get_file_url(self, fid, public=None):
          
          try:
              volume_id, rest = fid.strip().split(",")
          except ValueError:
              raise BadFidFormat(
                  "fid must be in format: <volume_id>,<file_name_hash>")
          file_location = self.get_file_location(volume_id)
          if public is None:
              public = self.use_public_url
          volume_url = file_location.public_url if public else file_location.url
          url = "http://{volume_url}/{fid}".format(
              volume_url=volume_url, fid=fid)
          return url
docs: Get url for the file
  
          :param string fid: File ID
          :param boolean public: public or internal url
          :rtype: string