Updating lecture files

...lec_notes/lec-35/lec_35_pandas3_data_transformation.ipynb

.../lec-35/lec_35_pandas3_data_transformation_template.ipynb

f22/meena_lec_notes/lec-36/lec_36_plotting1_bar_plots.ipynb

...ec_notes/lec-36/lec_36_plotting1_bar_plots_template.ipynb

...ena_lec_notes/lec-37/lec_36_plotting2_scatter_plots.ipynb

...otes/lec-37/lec_36_plotting2_scatter_plots_template.ipynb

...ena_lec_notes/lec-37/lec_37_plotting2_scatter_plots.ipynb

...otes/lec-37/lec_37_plotting2_scatter_plots_template.ipynb

...otes/lec-38/.ipynb_checkpoints/plotting1-checkpoint.ipynb

...38/.ipynb_checkpoints/plotting1_template-checkpoint.ipynb

f22/meena_lec_notes/lec-38/lec_37_plotting3_line_plots.ipynb

...c_notes/lec-38/lec_37_plotting3_line_plots_template.ipynb

f22/meena_lec_notes/lec-38/lec_38_plotting3_line_plots.ipynb

...c_notes/lec-38/lec_38_plotting3_line_plots_template.ipynb

...es/lec-39/.ipynb_checkpoints/demo_lec_38-checkpoint.ipynb

f22/meena_lec_notes/lec-39/lec_38_plotting4.ipynb

f22/meena_lec_notes/lec-39/lec_38_plotting4_template.ipynb

f22/meena_lec_notes/lec-39/lec_39_plotting4.ipynb

f22/meena_lec_notes/lec-39/lec_39_plotting4_template.ipynb