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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _GetVisibilityPolicy():
 """If a debugger configuration is found, create a visibility policy."""

  try:
    visibility_config = yaml_data_visibility_config_reader.OpenAndRead()
  except yaml_data_visibility_config_reader.Error as err:
    return error_data_visibility_policy.ErrorDataVisibilityPolicy(
        'Could not process debugger config: %s' % err)

  if visibility_config:
    return glob_data_visibility_policy.GlobDataVisibilityPolicy(
        visibility_config.blacklist_patterns,
        visibility_config.whitelist_patterns)

  return None