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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 _insert_entity(entity):
    '''
    Constructs an insert entity request.
    '''
    _validate_entity(entity)

    request = HTTPRequest()
    request.method = 'POST'
    request.headers = [_DEFAULT_CONTENT_TYPE_HEADER,
                        _DEFAULT_PREFER_HEADER,
                        _DEFAULT_ACCEPT_HEADER]
    request.body = _get_request_body(_convert_entity_to_json(entity))

    return request