code: def install_ca_cert(ca_cert, name=None):
      
      if not ca_cert:
          return
      if not isinstance(ca_cert, bytes):
          ca_cert = ca_cert.encode('utf8')
      if not name:
          name = 'juju-{}'.format(charm_name())
      cert_file = '/usr/local/share/ca-certificates/{}.crt'.format(name)
      new_hash = hashlib.md5(ca_cert).hexdigest()
      if file_hash(cert_file) == new_hash:
          return
      log("Installing new CA cert at: {}".format(cert_file), level=INFO)
      write_file(cert_file, ca_cert)
      subprocess.check_call(['update-ca-certificates', '--fresh'])
docs: Install the given cert as a trusted CA.
  
      The ``name`` is the stem of the filename where the cert is written, and if
      not provided, it will default to ``juju-{charm_name}``.
  
      If the cert is empty or None, or is unchanged, nothing is done.