code: def violin(n=500, dispersion=3, categories=True, n_categories=5):
      """
      Returns a DataFrame with the required format for
      a distribution plot (distplot)
  
      Parameters:
      -----------
              n : int
                      Number of points
              categories : bool or int
                      If True, then a column with categories is added
              n_categories : int
                      Number of categories
      """
      df = histogram(1, n, dispersion, "abc")
      df = df.rename(columns={"a": "data"})
      if categories:
          df["categories"] = [
              "category_{0}".format(np.random.randint(n_categories))
              for _ in range(n)
          ]
      return df
  
imports: import os
  import string
  import numpy
  import pandas
  from .auth import get_config_file
  from .exceptions import CufflinksError
label_desc: Use image node_id 16 for calling a global function with example usage: violin(n, dispersion, categories, n_categories) and returns: df