The >> sys.stderr part makes the print statement output to stderr instead of stdout in Python 2.
To quote the documentation:
print also has an extended form, defined by the second portion of the
syntax described above. This form is sometimes referred to as “print
chevron.” In this form, the first expression after the >> must
evaluate to a “file-like” object, specifically an object that has a
write() method as described above. With this extended form, the
subsequent expressions are printed to this file object. If the first
expression evaluates to None, then sys.stdout is used as the file for
output.
In Python 3 use the file argument to the print() function:
print("spam", file=sys.stderr)
