about ASAR data

[GaotTian]

file_name = 'ASA_WSM_1PNDSI20120309_155143_000003363112_00270_52439_0000.N1'
from pyroSAR.drivers import ESA
n = ESA(file_name)

this is a error :Traceback (most recent call last):
File "D:\Python_code\sea_ice_drift-master\MODIS_convert.py", line 31, in
n = ESA(file_name)
File "C:\software\anoconda3\envs\nansat3.8\lib\site-packages\pyroSAR\drivers.py", line 1519, in init
self.meta = self.scanMetadata()
File "C:\software\anoconda3\envs\nansat3.8\lib\site-packages\pyroSAR\drivers.py", line 1579, in scanMetadata
gcps = obj.read(size * n)
UnboundLocalError: local variable 'size' referenced before assignment