docs: def depends_statement(cookbook_name, metadata=None):
          """Return a valid Ruby 'depends' statement for the metadata.rb file."""
          line = "depends '%s'" % cookbook_name
          if metadata:
              if not isinstance(metadata, dict):
                  raise TypeError("Stencil dependency options for %s "
                                  "should be a dict of options, not %s."
                                  % (cookbook_name, metadata))
              if metadata:
                  line = "%s '%s'" % (line, "', '".join(metadata))
          return line