'Convenience method to create a schema object.
Example usage::
schema = Schema.create(hash_key=(\'foo\', \'N\'))
schema2 = Schema.create(hash_key=(\'foo\', \'N\'),
range_key=(\'bar\', \'S\'))
:type hash_key: tuple
:param hash_key: A tuple of (hash_key_name, hash_key_type)
:type range_key: tuple
:param hash_key: A tuple of (range_key_name, range_key_type)'

@classmethod
def create(cls, hash_key, range_key=None):

    reconstructed = {'HashKeyElement': {'AttributeName': hash_key[0], 'AttributeType': hash_key[1]}}
    if (range_key is not None):
        reconstructed['RangeKeyElement'] = {'AttributeName': range_key[0], 'AttributeType': range_key[1]}
    instance = cls(None)
    instance._dict = reconstructed
    return instance
