### `tf.contrib.layers.check_feature_columns(feature_columns)` {#check_feature_columns}

Checks the validity of the set of FeatureColumns.

##### Args:


*  <b>`feature_columns`</b>: A set of instances or subclasses of FeatureColumn.

##### Raises:


*  <b>`ValueError`</b>: If there are duplicate feature column keys.

