code: def _obtain_namespace(self, path_l):
      if len(path_l) == 1:
          # no nesting whatsoever
          return None
  
      try:
          namespace_id = self.site.groups.get(
              "/".join(path_l[:-1])
          ).get_id()
          lgr.debug(
              "Found existing parent group '%s' with ID %s",
              "/".join(path_l[:-1]),
              namespace_id,
          )
      except self.gitlab.GitlabGetError as e:
          try:
              if len(path_l) > 2:
                  parent_group = self.site.groups.get(
                      "/".join(path_l[:-2])
                  )
              else:
                  parent_group = None
          except self.gitlab.GitlabGetError as e:
              raise ValueError(
                  "No parent group {} for project {} found, "
                  "and a group {} also does not exist. At most one "
                  "parent group would be created.".format(
                      "/".join(path_l[:-1]),
                      "/".join(path_l),
                      "/".join(path_l[:-2]),
                  )
              )
          # create the group for the target project
          try:
              # prevent failure due to specification of a users personal
              # group, always exists, cannot and must not be created
              self.site.auth()
              if len(path_l) == 2 and path_l[
                  0
              ] == self.site.user.attributes.get("username", None):
                  # attempt to create a personal project in the users
                  # top-level personal group-- this is the same as
                  # having no parent namespace, don't attempt to
                  # create the group
                  return None
              namespace_id = self.site.groups.create(
                  dict(
                      name=path_l[-2],
                      path=path_l[-2],
                      parent_id=parent_group.get_id()
                      if parent_group
                      else None,
                  )
              ).get_id()
          except self.gitlab.GitlabCreateError as e:
              raise RuntimeError(
                  "Failed to create parent group '{}' under {}: {}".format(
                      path_l[-2],
                      repr(parent_group.attributes["full_path"])
                      if parent_group
                      else "the account root",
                      str(e),
                  ),
              )
      return namespace_id
  
imports: import logging
  import warnings
  from datalad.support.exceptions import CapturedException
  from ..distribution.dataset import EnsureDataset, datasetmethod, require_dataset, resolve_path
  from ..distribution.siblings import Siblings
  from ..dochelpers import exc_str
  from ..interface.base import Interface, build_doc, eval_results
  from ..interface.common_opts import publish_depends, recursion_flag, recursion_limit
  from ..local.subdatasets import Subdatasets
  from ..support.constraints import EnsureChoice, EnsureNone, EnsureStr
  from ..support.param import Parameter
  from ..utils import ensure_list
label_desc: Use image node_id 4 for calling the GitLabSite obj's underlying member method code with example usage: obj._obtain_namespace(path_l) and returns: namespace_id, None, None