docs: def _sparse(self, x, y, sparse):
          """
          Method that removes every non sparse th element.
  
          For example:
          if this argument was 5, This method would plot the 0th, 5th,
          10th ... elements.
  
          Parameters
          ----------
          x : list
              list of x values, of length j.
          y : list
              list of y values, of length j.
          sparse : integer
              Argument that skips every so many data points.
  
          """
          tmpX=[]
          tmpY=[]
  
          for i in range(len(x)):
              if sparse == 1:
                  return x,y
              if (i%sparse)==0:
                  tmpX.append(x[i])
                  tmpY.append(y[i])
          return tmpX, tmpY