'Load raw data.
Parameters
verbose : bool, str, int, or None
If not None, override default verbose level (see
:func:`mne.verbose` and :ref:`Logging documentation <tut_logging>`
for more).
Returns
raw : instance of Raw
The raw object with data.
Notes
This function will load raw data if it was not already preloaded.
If data were already preloaded, it will do nothing.
.. versionadded:: 0.10.0'

@verbose
def load_data(self, verbose=None):

    if (not self.preload):
        self._preload_data(True)
    return self
