Get the value of the enable-oslogin metadata key.

    Args:
      metadata_dict: json, the deserialized contents of the metadata server.

    Returns:
      bool, True if OS Login is enabled for VM access.

def _GetEnableOsLoginValue(self, metadata_dict):
    """Get the value of the enable-oslogin metadata key.

    Args:
      metadata_dict: json, the deserialized contents of the metadata server.

    Returns:
      bool, True if OS Login is enabled for VM access.
    """
    instance_data, project_data = self._GetInstanceAndProjectAttributes(
        metadata_dict)
    instance_value = instance_data.get('enable-oslogin')
    project_value = project_data.get('enable-oslogin')
    value = instance_value or project_value or ''

    return value.lower() == 'true'