class_docstr: Note: the Gantt charts listed here are inspired by
  Dustin Arendt and Svitlana Volkova. ESTEEM: A Novel Framework for Qualitatively Evaluating and
  Visualizing Spatiotemporal Embeddings in Social Media. ACL System Demonstrations. 2017.
  http://www.aclweb.org/anthology/P/P17/P17-4005.pdf
  
  In order to use the make chart function, Altair must be installed.
class_docstr_tok: ["Note",":","the","Gantt","charts","listed","here","are","inspired","by","Dustin","Arendt","and","Svitlana","Volkova",".","ESTEEM",":","A","Novel","Framework","for","Qualitatively","Evaluating","and","Visualizing","Spatiotemporal","Embeddings","in","Social","Media",".","ACL","System","Demonstrations",".","2017.","http",":","\/\/www.aclweb.org\/anthology\/P\/P17\/P17-4005.pdf","In","order","to","use","the","make","chart","function",",","Altair","must","be","installed","."]
docstr: Returns
  -------
  altair.Chart
docstr_tok: ["Returns","--","--","--","-","altair.Chart"]
code: def make_chart(self):
      """
      Returns
      -------
      altair.Chart
      """
      task_df = self.get_task_df()
      import altair as alt
  
      chart = (
          alt.Chart(task_df)
          .mark_bar()
          .encode(
              x="start",
              x2="end",
              y="term",
          )
      )
      return chart
  
file_path: scattertext/scattertext/diachronic/GanttChart.py
imports: import numpy
  import pandas
  from scattertext.termranking import AbsoluteFrequencyRanker
  from scattertext.termscoring.RankDifference import RankDifference
label_desc: Use image node_id 2 for calling the GanttChart obj's underlying member method code with example usage: obj.make_chart() and returns: chart