code: def pem_armor_csr(certification_request):
      
  
      if not isinstance(certification_request, csr.CertificationRequest):
          raise TypeError(_pretty_message(
              '''
              certification_request must be an instance of
              asn1crypto.csr.CertificationRequest, not %s
              ''',
              _type_name(certification_request)
          ))
  
      return pem.armor(
          'CERTIFICATE REQUEST',
          certification_request.dump()
      )
docs: Encodes a CSR into PEM format
  
      :param certification_request:
          An asn1crypto.csr.CertificationRequest object of the CSR to armor.
          Typically this is obtained from CSRBuilder.build().
  
      :return:
          A byte string of the PEM-encoded CSR