无法安装gmplot软件包

Question

我想安装gmplot软件包，但无济于事，总是得到相同的错误：

Collecting gmplot
  WARNING: Retrying (Retry(total=4, connect=None, read=None, redirect=None, status=None)) after 
connection broken by 'SSLError(SSLCertVerificationError(1, '[SSL: CERTIFICATE_VERIFY_FAILED] 
certificate verify failed: self signed certificate in certificate chain (_ssl.c:1051)'))': 
/simple/gmplot/

Could not fetch URL https://pypi.org/simple/gmplot/: There was a problem confirming the ssl 
certificate: HTTPSConnectionPool(host='pypi.org', port=443): Max retries exceeded with url: 
/simple/gmplot/ (Caused by SSLError(SSLCertVerificationError(1, '[SSL: CERTIFICATE_VERIFY_FAILED] 
certificate verify failed: self signed certificate in certificate chain (_ssl.c:1051)'))) - skipping

  ERROR: Could not find a version that satisfies the requirement gmplot (from versions: none)
ERROR: No matching distribution found for gmplot

可能是问题所在，如何安装gmplot？

谢谢！