code: @Override
      public void removeMonomer(String name) {
          if (monomers.containsKey(name)) {
              Monomer monomer = (Monomer) monomers.get(name);
              this.remove(monomer);
              monomers.remove(name);
          }
      }
docs: Removes a particular monomer, specified by its name.
  
  @param name The name of the monomer to remove