class_docstr: Mark a function or class as deprecated (decorator).
  
  Issue a warning when the function is called/the class is instantiated and
  adds a warning to the docstring.
  
  The optional extra argument will be appended to the deprecation message
  and the docstring. Note: to use this with the default value for extra, put
  in an empty of parentheses::
  
      >>> from pyriemann.utils import deprecated
      >>> deprecated()
      <pyriemann.utils.docs.deprecated object at ...>
      >>> @deprecated()
      ... def some_function(): pass
  
  
  Parameters
  ----------
  extra: string
      To be added to the deprecation messages.
code: def _update_doc(self, olddoc):
      newdoc = ".. warning:: DEPRECATED"
      if self.extra:
          newdoc = "%s: %s" % (newdoc, self.extra)
      if olddoc:
          # Get the spacing right to avoid sphinx warnings
          n_space = 4
          for li, line in enumerate(olddoc.split("\n")):
              if li > 0 and len(line.strip()):
                  n_space = len(line) - len(line.lstrip())
                  break
          newdoc = "%s\n\n%s%s" % (newdoc, " " * n_space, olddoc)
  
      return newdoc
  
file_path: pyRiemann/pyriemann/utils/docs.py
imports: import warnings
label_desc: Use image node_id 5 for calling the deprecated obj's underlying member method code with example usage: obj._update_doc(olddoc) and returns: newdoc