class_docstr: Base class for TPU Embedding Column.
class_docstr_tok: ["Base","class","for","TPU","Embedding","Column","."]
docstr: Returns the feature key name in the features dict.
docstr_tok: ["Returns","the","feature","key","name","in","the","features","dict","."]
code: def get_feature_key_name(self):
      """Returns the feature key name in the features dict."""
      raise NotImplementedError("not impl")
  
imports: import math
  from tensorflow.python.feature_column import feature_column
  from tensorflow.python.feature_column import feature_column_lib
  from tensorflow.python.framework import ops
  from tensorflow.python.ops import array_ops
  from tensorflow.python.ops import init_ops
  from tensorflow.python.ops import variable_scope
  from tensorflow.python.tpu import tpu
  from tensorflow.python.tpu import tpu_function
  from tensorflow.python.tpu import tpu_replication
label_desc: Use image node_id 4 for calling the _TPUBaseEmbeddingColumn obj's underlying member method code with example usage: obj.get_feature_key_name() without return types