Use strings as parameters for Matplotlib

I want to generate parameters for figures dynamically, pass as arguments to Matplotlib.

Example to illustrate, this works:

dict = {'x_tick_fontsize':12 ,'x_tick_weight':'normal','x_tick_rotation':15}
            
plt.xticks(fontsize = dict['x_tick_fontsize']  
           ,weight = dict['x_tick_weight'] 
           ,rotation = dict['x_tick_rotation']) 

This doesn't, but I want it to:

my_params_string = "fontsize = 12, weight ='normal', rotation = 15"
plt.xticks(my_params_string)

What can I try next?