def _set_elangles(self):
        """Sets the values of instance variable elangles.
        
        Method creates a dictionary containing the elangles of the pvol file.
        Elangles are ordered in acending order using uppercase letters as keys
        
        Examples
        --------
        >>> pvol = OdimPVOL('pvol.h5')
        >>> print(pvol.elangles)
        {'A': 0.5, 'C': 1.5, 'B': 0.69999999999999996, 'E': 5.0, 'D': 3.0}
        """
        elang_list = list(self.attr_gen('elangle'))
        try:
            elevation_angles = sorted(zip(*elang_list)[1])
            n_elangles = len(elevation_angles)
            self.elangles = dict(zip(list(string.ascii_uppercase[:n_elangles]), elevation_angles))
        except IndexError:
            self.elangles = {}
Sets the values of instance variable elangles.
        
        Method creates a dictionary containing the elangles of the pvol file.
        Elangles are ordered in acending order using uppercase letters as keys
        
        Examples
        --------
        >>> pvol = OdimPVOL('pvol.h5')
        >>> print(pvol.elangles)
        {'A': 0.5, 'C': 1.5, 'B': 0.69999999999999996, 'E': 5.0, 'D': 3.0}