class_docstr: Base class for TPU Embedding Column.
class_docstr_tok: ["Base","class","for","TPU","Embedding","Column","."]
docstr: Returns the embedding variable name.
  
  Feature key name and embedding variable name are usually one-to-one mapping.
  But for shared embedding columns, it is many-to-one mapping.
docstr_tok: ["Returns","the","embedding","variable","name",".","Feature","key","name","and","embedding","variable","name","are","usually","one-to-one","mapping",".","But","for","shared","embedding","columns",",","it","is","many-to-one","mapping","."]
code: def get_embedding_var_name(self):
      """Returns the embedding variable name.
  
      Feature key name and embedding variable name are usually one-to-one mapping.
      But for shared embedding columns, it is many-to-one mapping.
      """
      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 6 for calling the _TPUBaseEmbeddingColumn obj's underlying member method code with example usage: obj.get_embedding_var_name() without return types