code: def get_page_horz_percentile(
      mention, page_width=DEFAULT_WIDTH, page_height=DEFAULT_HEIGHT
  ):
      
      span = _to_span(mention)
      return bbox_from_span(span).left / page_width
docs: Return which percentile from the LEFT in the page the Mention is located in.
  
      Percentile is calculated where the left of the page is 0.0, and the right
      of the page is 1.0.
  
      Page width and height are based on pt values::
  
          Letter      612x792
          Tabloid     792x1224
          Ledger      1224x792
          Legal       612x1008
          Statement   396x612
          Executive   540x720
          A0          2384x3371
          A1          1685x2384
          A2          1190x1684
          A3          842x1190
          A4          595x842
          A4Small     595x842
          A5          420x595
          B4          729x1032
          B5          516x729
          Folio       612x936
          Quarto      610x780
          10x14       720x1008
  
      and should match the source documents. Letter size is used by default.
  
      Note that if a candidate is passed in, only the vertical percentile of its
      first Mention is returned.
  
      :param c: The Mention to evaluate
      :param page_width: The width of the page. Default to Letter paper width.
      :param page_height: The heigh of the page. Default to Letter paper height.
      :rtype: float in [0.0, 1.0]