'Write this object to a file. The object can be restored by calling MetaArray(file=fileName)
opts:
appendAxis: the name (or index) of the appendable axis. Allows the array to grow.
compression: None, \'gzip\' (good compression), \'lzf\' (fast compression), etc.
chunks: bool or tuple specifying chunk shape'

def write(self, fileName, **opts):

    if (USE_HDF5 and HAVE_HDF5):
        return self.writeHDF5(fileName, **opts)
    else:
        return self.writeMa(fileName, **opts)
