gistfile1.txt

dct = {
    'thing1': 'a',
    'thing3': 'c',
    'thing4': 'd',
    'thing5': 'e'
}

def plotting_function(thing1=None, thing2=None, thing3=None, **kwargs):
    print('thing1 = %s' % thing1)
    print('thing2 = %s' % thing2)
    print('thing3 = %s' % thing3)
    print('kwargs = {}'.format(kwargs))
    
plotting_function(**dct)

"""Outputs the following:
thing1 = a
thing2 = None
thing3 = c
kwargs = {'thing4': 'd', 'thing5': 'e'}
"""