plot legends for subplots properly

Fixing plotting subplots by removing duplication for subplot definition and using axes for creating legends

Description

This is a fix for the plots of function plot_error_band for AGIPD's FF notebook.

Image with plotting Warning and bug.

How Has This Been Tested?

xfel-calibrate AGIPD FF \
--in-folder /gpfs/exfel/exp/SPB/202031/p900146/proc/proc_vtst/p900215/FF/HISTS/64cells1.1MHz_gs0_12clk/r96/ \
--out-folder /gpfs/exfel/data/scratch/ahmedk/test/FF_plot \
--proc-folder /gpfs/exfel/exp/SPB/202131/p900215/proc/ \
--raw-folder /gpfs/exfel/exp/SPB/202131/p900215/raw/ \
--karabo-id-control SPB_IRU_AGIPD1M1 --karabo-id SPB_DET_AGIPD1M-1 \
--modules 0-16 --cell-range 0 64 --acq-rate 1.1 --gain-setting 0 \
--run 96 --peak-range -30 20 30 80 80 150 135 200 \
--peak-width-range 0 20 0 35 0 35 0 40 --peak-lim -20 20 \
--d0-lim 35 80 --peak-width-lim 0.5 2.0 0.5 2.0 --chi2-lim 0 4 \
--gain-lim 0.6 1.4 --pixel-range 0 0 512 128 --fit-range -40 160 \
--n-peaks-fit 3 --sigma-limit 1.5 --slurm-name TestFFSPB \
--slurm-mem 750

Relevant Documents (optional)

Report after the fix: GainCharacterization_1_.pdf

Types of changes

• Bug fix (non-breaking change which fixes an issue)

Checklist:

Reviewers

@danilevc @jsztuk