Escape column_name in hypertransformer

[csala]

The column name is being used in the HyperTransformer class to generate a regular expression that later on is used to identify which transformed columns need to be used to revert the transformation:

RDT/rdt/hyper_transformer.py

Line 194 in 79195ef

regex = r'{}(#[0-9]+)?$'.format(column_name)

This column name should be escaped to avoid conflicts when there are symbols that can be interpreted as regex escape sequences.