pip3 +python3.7 Error: There was a problem confirming the ssl certificate

Retrying (Retry(total=4, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError(SSLError("bad handshake: Error([('SSL routines', 'tls_process_server_certificate', 'certificate verify failed')])"))': /simple/beautifulsoup4/
  Retrying (Retry(total=3, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError(SSLError("bad handshake: Error([('SSL routines', 'tls_process_server_certificate', 'certificate verify failed')])"))': /simple/beautifulsoup4/
  Retrying (Retry(total=2, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError(SSLError("bad handshake: Error([('SSL routines', 'tls_process_server_certificate', 'certificate verify failed')])"))': /simple/beautifulsoup4/
  Retrying (Retry(total=1, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError(SSLError("bad handshake: Error([('SSL routines', 'tls_process_server_certificate', 'certificate verify failed')])"))': /simple/beautifulsoup4/
  Retrying (Retry(total=0, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError(SSLError("bad handshake: Error([('SSL routines', 'tls_process_server_certificate', 'certificate verify failed')])"))': /simple/beautifulsoup4/
  Could not fetch URL https://pypi.org/simple/beautifulsoup4/: There was a problem confirming the ssl certificate: HTTPSConnectionPool(host='pypi.org', port=443): Max retries exceeded with url: /simple/beautifulsoup4/ (Caused by SSLError(SSLError("bad handshake: Error([('SSL routines', 'tls_process_server_certificate', 'certificate verify failed')])"))) - skipping
  Could not find a version that satisfies the requirement beautifulsoup4 (from versions: )
No matching distribution found for beautifulsoup4

Due to the ssl libs, so should indicate the pip source is safe.

pip3 install beautifulsoup4 -i http://pypi.douban.com/simple --trusted-host pypi.douban.com