Dropdown bar chart (plotly) based on values column

Can someone help me how to make add a “dropdown” menu in a plotly-bar chart.
I’ve found some information on the following link (https://plot.ly/python/v3/dropdowns/) but I’m struggling to adapt the code, so the dropdown options are all (unique) values in a certain column)

E.g. a (Part of my table is the following:

date	    Reason      	name	        Task
2019-11-17	AI	            CHRISTOPHE	    3
2019-10-27	RANDOM	        CHRISTOPHE		19
2019-11-03	RANDOM	        CHRISTOPHE		19
2019-11-10	RANDOM		    CHRISTOPHE		49
2019-11-17	RANDOM		    CHRISTOPHE		26
2019-10-27	AI	            FERRANTE	    29
2019-11-03	AI	            FERRANTE	    40
2019-11-17	AI	            FERRANTE	    26
2019-10-27	RANDOM		    FERRANTE	    1
2019-11-03	RANDOM		    FERRANTE	    4
2019-11-10	RANDOM		    FERRANTE	    2 
2019-11-17	RANDOM		    FERRANTE	    2

I would love to have a plotly bar plot showing per date the number of allocated task per “reason” and a dropdown menu where I can select the names in the ‘name’ col.