code: def _set_matplotlib_default_backend():
      
      if _matplotlib_installed():
          import matplotlib
          matplotlib.use('Agg', force=True)
          config = matplotlib.matplotlib_fname()
          if os.access(config, os.W_OK):
              with file_transaction(config) as tx_out_file:
                  with open(config) as in_file, open(tx_out_file, "w") as out_file:
                      for line in in_file:
                          if line.split(":")[0].strip() == "backend":
                              out_file.write("backend: agg\n")
                          else:
                              out_file.write(line)
docs: matplotlib will try to print to a display if it is available, but don't want
      to run it in interactive mode. we tried setting the backend to 'Agg'' before
      importing, but it was still resulting in issues. we replace the existing
      backend with 'agg' in the default matplotlibrc. This is a hack until we can
      find a better solution