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Given the following text description, write Python code to implement the functionality described below step by step
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Description:
 Reading and writing an evoked file
This script shows how to read and write evoked datasets.
Step1:  Show result as a butterfly plot
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Python Code:
# Author: Alexandre Gramfort <alexandre.gramfort@inria.fr>
#
# License: BSD (3-clause)
from mne import read_evokeds
from mne.datasets import sample
print(__doc__)
data_path = sample.data_path()
fname = data_path + '/MEG/sample/sample_audvis-ave.fif'
# Reading
condition = 'Left Auditory'
evoked = read_evokeds(fname, condition=condition, baseline=(None, 0),
                      proj=True)
Explanation: Reading and writing an evoked file
This script shows how to read and write evoked datasets.
End of explanation
evoked.plot(exclude=[], time_unit='s')
# Show result as a 2D image (x: time, y: channels, color: amplitude)
evoked.plot_image(exclude=[], time_unit='s')
Explanation: Show result as a butterfly plot:
By using exclude=[] bad channels are not excluded and are shown in red
End of explanation
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