code: def visit_FormattedValue(self, node):
          
          self.result += '{'
          self.visit(node.value)
          self.result += {
              -1: '',     # no formatting
              97: '!a',   # ascii formatting
              114: '!r',  # repr formatting
              115: '!s',  # string formatting
          }[node.conversion]
          if node.format_spec:
              self.result += ':'
              self.visit_joined_str(node.format_spec)
          self.result += '}'
docs: FormattedValue(expr value, int? conversion, expr? format_spec)