docs: def yaml_from_file(self, fpath):
          """Collect Parameter stanzas from inline + file.
  
          This allows use to reference an external file for the actual
          parameter definitions.
          """
  
          lookup = self._load_param_file(fpath)
          if not lookup:
              return
  
          content = "\n".join(self.content)
          parsed = yaml.safe_load(content)
          # self.app.info("Params loaded is %s" % parsed)
          # self.app.info("Lookup table looks like %s" % lookup)
          new_content = list()
          for paramlist in parsed:
              if not isinstance(paramlist, dict):
                  self.app.warn(
                      ("Invalid parameter definition ``%s``. Expected "
                       "format: ``name: reference``. "
                       " Skipping." % paramlist),
                      (self.state_machine.node.source,
                       self.state_machine.node.line))
                  continue
              for name, ref in paramlist.items():
                  if ref in lookup:
                      new_content.append((name, lookup[ref]))
                  else:
                      self.app.warn(
                          ("No field definition for ``%s`` found in ``%s``. "
                           " Skipping." % (ref, fpath)),
                          (self.state_machine.node.source,
                           self.state_machine.node.line))
  
          # self.app.info("New content %s" % new_content)
          self.yaml = new_content