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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 _delete_entity(partition_key, row_key, if_match):
    '''
     Constructs a delete entity request.
    '''
    _validate_not_none('if_match', if_match)
    _validate_not_none('partition_key', partition_key)
    _validate_not_none('row_key', row_key)
    request = HTTPRequest()
    request.method = 'DELETE'
    request.headers = [_DEFAULT_ACCEPT_HEADER,
                        ('If-Match', _to_str(if_match))]

    return request