Added the necessay import of module

[ankur0904]

What does this PR do?

When I was following the tutorial and running the cells for tensorflow

Then at this code block for Keras I got the error np is not defined

from transformers import AutoTokenizer

tokenizer = AutoTokenizer.from_pretrained("google-bert/bert-base-cased")
tokenized_data = tokenizer(dataset["sentence"], return_tensors="np", padding=True)
# Tokenizer returns a BatchEncoding, but we convert that to a dict for Keras
tokenized_data = dict(tokenized_data)

labels = np.array(dataset["label"])  # Label is already an array of 0 and 1

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[amyeroberts]

Thanks for fixing!