code: def set_dependencies(self, id, internal=list(), external=list()):
          
          dependency_str = 'NONE'
          if len(internal) > 0 or len(external) > 0:
              deps = internal
              for (name, link) in external:
                  deps.append("{0}@{1}".format(name, link))
              dependency_str = '$'.join(str(x) for x in deps)
  
          params = {
              'string': b64encode(dependency_str.encode('ascii'))
          }
  
          url = self._base + 'lot/{0}/dependency-string'.format(id)
          r = requests.put(url, auth=self._auth, params=params)
          r.raise_for_status()
  
          return {
              'plain': dependency_str,
              'encoded': params['string']
          }
docs: Sets the dependency string (for the LEX Dependency Tracker) for a lot.
          Requires administrator access.
          :param id: Identifier of the lot
          :param internal: List of dependency identifiers for internal files (LEX lots) that the lot depends on
          :param external: List of (name, link) tuples for external files (STEX, TSC, ...) that the lot depends on
          :return: Created dependency string that was sent to the server, in plaintext and base64 encoded
          :rtype: str