code: def _convert_coordinates_to_decimal_degrees(
              self):
          
          self.log.info(
              'starting the ``_convert_coordinates_to_decimal_degrees`` method')
  
          converter = unit_conversion(
              log=self.log
          )
  
          # CONVERT ALL COORDINATES TO DECIMAL DEGREES
          if len(self.listOfCoordinates) and isinstance(self.listOfCoordinates[0], str):
              sources = []
              sources[:] = [s.split(" ") for s in self.listOfCoordinates]
  
          else:
              sources = self.listOfCoordinates
          self.listOfCoordinates = []
  
          # TEST IF CONVERSION IS REQUIRED
          try:
              ra = float(sources[0][0])
              convert = False
          except:
              convert = True
  
          if convert == True:
              raDegs = []
              raDegs[:] = [converter.ra_sexegesimal_to_decimal(
                  ra=s[0]) for s in sources]
              decDegs = []
              decDegs[:] = [converter.dec_sexegesimal_to_decimal(
                  dec=s[1]) for s in sources]
              self.listOfCoordinates = []
              self.listOfCoordinates[:] = [[raDeg, decDeg]
                                           for raDeg, decDeg in zip(raDegs, decDegs)]
  
          else:
              self.listOfCoordinates = []
              self.listOfCoordinates[:] = [[float(s[0]), float(s[1])]
                                           for s in sources]
  
          self.log.info(
              'completed the ``_convert_coordinates_to_decimal_degrees`` method')
          return None
docs: *convert coordinates to decimal degrees*