code: def get_certificate():
      ''' Read openvswitch certificate from disk '''
      if os.path.exists(CERT_PATH):
          log('Reading ovs certificate from {}'.format(CERT_PATH))
          with open(CERT_PATH, 'r') as cert:
              full_cert = cert.read()
              begin_marker = "-----BEGIN CERTIFICATE-----"
              end_marker = "-----END CERTIFICATE-----"
              begin_index = full_cert.find(begin_marker)
              end_index = full_cert.rfind(end_marker)
              if end_index == -1 or begin_index == -1:
                  raise RuntimeError("Certificate does not contain valid begin"
                                     " and end markers.")
              full_cert = full_cert[begin_index:(end_index + len(end_marker))]
              return full_cert
      else:
          log('Certificate not found', level=WARNING)
          return Nonf get_certificate():
      ''' Read openvswitch certificate from disk '''
      if os.path.exists(CERT_PATH):
          log('Reading ovs certificate from {}'.format(CERT_PATH))
          with open(CERT_PATH, 'r') as cert:
              full_cert = cert.read()
              begin_marker = "-----BEGIN CERTIFICATE-----"
              end_marker = "-----END CERTIFICATE-----"
              begin_index = full_cert.find(begin_marker)
              end_index = full_cert.rfind(end_marker)
              if end_index == -1 or begin_index == -1:
                  raise RuntimeError("Certificate does not contain valid begin"
                                     " and end markers.")
              full_cert = full_cert[begin_index:(end_index + len(end_marker))]
              return full_cert
      else:
          log('Certificate not found', level=WARNING)
          return None
docs: Read openvswitch certificate from disk