Notation fixing in code

[Alberto-o]

There is a certain incoherence in the choice of variable names throughout the code so far, with uses of var_name, VarName or Varname To avoid further confusions, they should be changed to reflect the naming convention in https://stackoverflow.com/questions/159720/what-is-the-naming-convention-in-python-for-variable-and-function-names/8423697#8423697