Large Column Labels: rotate the text up to 90 degrees?

Question

I have too large column labels as on the example belows. How Could I rotate the header labels up to 90 degrees? Have you any idea how can I do it easy way ?

import sys
from PyQt4.QtCore import *
from PyQt4.QtGui import *

data = {'Large Table Columns 1':['1','2','3'], 'Large Table Columns 2':['4','5','6'], 'Large Table Columns 3':['7','8','9']}

class MyTable(QTableWidget):
    def __init__(self, data, *args):
        QTableWidget.__init__(self, *args)
        self.data = data
        self.setmydata()
        self.resizeColumnsToContents()
        self.resizeRowsToContents()

    def setmydata(self):

        horHeaders = []
        for n, key in enumerate(sorted(self.data.keys())):
            horHeaders.append(key)
            for m, item in enumerate(self.data[key]):
                newitem = QTableWidgetItem(item)
                self.setItem(m, n, newitem)
        self.setHorizontalHeaderLabels(horHeaders)

def main(args):
    app = QApplication(args)
    table = MyTable(data, 5, 3)
    table.show()
    sys.exit(app.exec_())

if __name__=="__main__":
    main(sys.argv)