a = """[
             [["L1603",1,5],[271585,972739],[272739,872739, 272739,972739, 271585,972739, 271585,272389, 270999,272389]],
             [["L1605",1,5],[271897,872739],[272739,872739, 272739,972739, 271891,872739, 271891,272119, 270963,272119]],
             [["L1607",1,4],[271584,272738],[271584,272738, 271584,272388, 270998,272388, 270998,272386]]
            ]
"""
import ast
ast.literal_eval(a)
Importing a 3-D list variable from a text file in Python