$ pyuic4 lfdsampler_2.ui -o lfdsampler.py -d
Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/PyQt4/uic/port_v2/invoke.py", line 39, in invoke
    exit_status = driver.invoke()
  File "/usr/lib/python2.7/dist-packages/PyQt4/uic/driver.py", line 64, in invoke
    self._generate()
  File "/usr/lib/python2.7/dist-packages/PyQt4/uic/driver.py", line 99, in _generate
    self._opts.resource_suffix)
  File "/usr/lib/python2.7/dist-packages/PyQt4/uic/__init__.py", line 175, in compileUi
    winfo = compiler.UICompiler().compileUi(uifile, pyfile, from_imports, resource_suffix)
  File "/usr/lib/python2.7/dist-packages/PyQt4/uic/Compiler/compiler.py", line 55, in __init__
    CompilerCreatorPolicy())
  File "/usr/lib/python2.7/dist-packages/PyQt4/uic/uiparser.py", line 170, in __init__
    self.factory = QObjectCreator(creatorPolicy)
  File "/usr/lib/python2.7/dist-packages/PyQt4/uic/objcreator.py", line 94, in __init__
    modinfo = plugin_locals["moduleInformation"]()
  File "<string>", line 52, in moduleInformation
  File "/usr/lib/python2.7/dist-packages/qgis/__init__.py", line 26, in <module>
    from qgis.PyQt import QtCore
  File "/usr/lib/python2.7/dist-packages/qgis/PyQt/QtCore.py", line 28, in <module>
    sip.setapi(api, 2)
ValueError: API 'QDate' has already been set to version 1