'Constructor.'

def __init__(self, filename, file_handle, mmap_mode=None):

    self._filename = os.path.basename(filename)
    self._dirname = os.path.dirname(filename)
    self.mmap_mode = mmap_mode
    self.file_handle = self._open_pickle(file_handle)
    Unpickler.__init__(self, self.file_handle)
    try:
        import numpy as np
    except ImportError:
        np = None
    self.np = np
