docs: def siblingExtensionSearch(self, *exts):
          """Attempt to return a path with my name, given multiple possible
          extensions.
  
          Each extension in exts will be tested and the first path which exists
          will be returned.  If no path exists, None will be returned.  If '' is
          in exts, then if the file referred to by this path exists, 'self' will
          be returned.
  
          The extension '*' has a magic meaning, which means "any path that
          begins with self.path+'.' is acceptable".
          """
          p = self.path
          for ext in exts:
              if not ext and self.exists():
                  return self
              if ext == '*':
                  basedot = basename(p)+'.'
                  for fn in listdir(dirname(p)):
                      if fn.startswith(basedot):
                          return self.clonePath(joinpath(dirname(p), fn))
              p2 = p + ext
              if exists(p2):
                  return self.clonePath(p2)