Aplications raise except TypeError

[isvaldo]

Traceback (most recent call last):
File "init.py", line 73, in
SetDB().write_file_pdi()
File "init.py", line 64, in write_file_pdi
tree.write(file, encoding='utf-8', xml_declaration=True)
File "/usr/lib/python2.7/xml/etree/ElementTree.py", line 812, in write
write("\n" % encoding)
TypeError: descriptor 'write' requires a 'file' object but received a 'str'

maybe, "file" is a mistake ?
tree.write(file, encoding='utf-8', xml_declaration=True)

@dmvieira
@thiagopf