问AttributeError：'NoneType‘对象没有'startswith’属性

EN

import requests
import pygal
from pygal.style import LightColorizedStyle as LCS, LightenStyle as LS


url = "https://api.github.com/search/repositories? 
q=language:python&sort=stars"
r = requests.get(url)

response_dict = r.json()

names,stars = [],[]
for repo in repo_dicts:
    names.append(repo["name"])
    stars.append(repo["stargazers_count"])

my_style = LS("333366", base_style=LCS)
chart = pygal.Bar(style=my_style, x_label_rotation=45, show_legend=False)
chart.title = "Most starred Python projects on GitHub"
chart.x_labels = names

chart.add(" ", stars)
chart.render_to_file("repo_visual.svg")

Traceback (most recent call last):
File "C:/Users/user/PycharmProjects/generatingdata/python_repos.py", line 
51, in <module>
chart.render_to_file("x.svg")