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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 _check_boolean(parameter_name, value, parameter_config):
 """Checks if a boolean value is valid. This is called by the transform_parameter_value function and shouldn't be called directly. This checks that the string value passed in can be converted to a valid boolean value. Args: parameter_name: A string containing the name of the parameter, which is either just a variable name or the name with the index appended. For example 'var' or 'var[2]'. value: A string containing the value passed in for the parameter. parameter_config: The dictionary containing information specific to the parameter in question. This is retrieved from request.parameters in the method config. Raises: BasicTypeParameterError: If the given value is not a valid boolean value. """

  if parameter_config.get('type') != 'boolean':
    return

  if value.lower() not in ('1', 'true', '0', 'false'):
    raise errors.BasicTypeParameterError(parameter_name, value, 'boolean')