Non-constant expressions cannot be multiplied - PuLP Package

Question

I am working on an optimisation problem for which I am using PuLP lienar programming package. Please find my linear programming model parameters below: #model model = LpProblem(name="variable_rate", sense = LpMaximize)

Defining variable

var_rate = LpVariable.dicts("variable_rate", len, lowBound=10, upBound=26, cat='integer')

expression = variable_xvar_ratevar_rate #part of the expression

I get the error 'TypeError: Non-constant expressions cannot be multiplied'

So, if my expression involves multiplication of the LpVariable, I get this error. I read that PuLP is a linear programming package and accepts only addition or subtraction within the LpVariable. But I need to have that multiplication factor in my expression. Is there a way I can solve this problem with PuLP or do you suggest any other optimisation package.

Thank you in advance.