.data.sub_()

As an AI language model, I am not sure about the specific programming language or context you are referring to. However, in general, the method `.data.sub_()` might refer to a function or method in a programming language that modifies or subtracts a value from a variable or data structure.

For example, in Python, the method `.sub_()` could be used with a NumPy array to subtract a given value from each element in the array. The underscore at the end of the method name indicates that the operation is performed in-place, meaning that the original array is modified rather than creating a new copy.

Here is an example code snippet using the `.sub_()` method in Python:

import numpy as np

# create a NumPy array
arr = np.array([1, 2, 3, 4, 5])

# subtract 2 from each element in the array
arr.sub_(2)

# print the modified array
print(arr)

This would output:

[-1  0  1  2  3]

Again, this is just one example and the usage and implementation of `.data.sub_()` might vary depending on the programming language or context.