Finds the depth of a mathematical expression. It follows the syntax expr = ('operator','term1','term2',...,'termN')

expression_depth.py

def depth(expr):
    depthLevel = 0
    if(isinstance(expr,(list,tuple))==False):
        return 0
    else:
        depthLevel += 1
        if( isinstance(expr[1],(list,tuple)) ):
            biggestDepth = 0
            for i in range(1,len(expr)):
                depthOfCurrentTerm = depth(expr[i])
                if depthOfCurrentTerm > biggestDepth:
                    biggestDepth = depthOfCurrentTerm
            depthLevel += biggestDepth
        return depthLevel