Files _1D_Dirac_Crystal.py and two_identical_impurities.py contain classses Crystal and TwoSameImpurities. Class Crystal represents one-dimentional crystal of charged impurities of finite size. Class TwoSameImpurities corresponds to the special case of 2 identical positively charged impurities. Fields of these calasses describe the crystal characteristics and methods may be used to calculate the eigenstates (bound state energies and corresponding wavefunctions), local density of states (LDOS) and its dependence on crystal parameters. File main.py provides an example of use.