parameters: (cls, style_dict, num_format_str=None)
return_statement: return style
docstring: converts a style_dict to an xlwt style object
  
          Parameters
          ----------
          style_dict : style dictionary to convert
          num_format_str : optional number format string
docstring_summary: converts a style_dict to an xlwt style object
docstring_tokens: converts a style_dict to an xlwt style object
function: def _convert_to_style(cls, style_dict, num_format_str=None):
          """
          converts a style_dict to an xlwt style object
  
          Parameters
          ----------
          style_dict : style dictionary to convert
          num_format_str : optional number format string
          """
          import xlwt
  
          if style_dict:
              xlwt_stylestr = cls._style_to_xlwt(style_dict)
              style = xlwt.easyxf(xlwt_stylestr, field_sep=",", line_sep=";")
          else:
              style = xlwt.XFStyle()
          if num_format_str is not None:
              style.num_format_str = num_format_str
  
          return style
function_tokens: def _convert_to_style ( cls , style_dict , num_format_str = None ) : import xlwt if style_dict : xlwt_stylestr = cls . _style_to_xlwt ( style_dict ) style = xlwt . easyxf ( xlwt_stylestr , field_sep = "," , line_sep = ";" ) else : style = xlwt . XFStyle ( ) if num_format_str is not None : style . num_format_str = num_format_str return style