def style_chg_label(self,type,symb=None,edc=None,fac=None,smbsz=None,edw=None,lab=None):
        '''
        This routine changes the plotting style that is set by default.
        The style is changed according the the label that you choose.
        Changing according to reference, use style_chg_ref() function!
        You can change it back to default by resetting the filter using
        g.reset_filter() routine, assuming that g is your instance. The
        format that is used here is:

        ['Symbol', 'Edge color', 'Face color', 'Symbol size', 'Edge width'
        ,'Label']

        You can see the current styles by running

        Attention: You have to give values to all variables that are
        compatible with the python mathplotlib. If not, it's your fault
        if nothing works.

        g.style

        Parameters
        ----------
        type : string
            Select the label of the grains you want to change.
        symb : string, optional
            Select new symbol. None for no change.
        edc : string, optional
            Select new edge color. None for no change.
        fac : string, optional
            Select new face color. None for no change.
        smbsz : string, optional
            Select new symbol size. None for no change.
        edw : string, optional
            Select new edge width. None for no change.
        lab : string, optional
            Select new label. None for no change. Watch out, if you
            want to do more specifications later, the type will
            have changed to the new label.
        '''

        # do stuff for selected type
        for i in range(len(self.style)):
            # check if type is correct, otherwise continue directly
            if self.style[i][self.styledict['Label']] == type:
                # change symbol:
                if symb != None:
                    self.style[i][self.styledict['Symbol']] = symb
                # change edge color
                if edc != None:
                    self.style[i][self.styledict['Edge color']] = edc
                # change face color
                if fac != None:
                    self.style[i][self.styledict['Face color']] = fac
                # change symbol size
                if smbsz != None:
                    self.style[i][self.styledict['Symbol size']] = smbsz
                # change edge width
                if edw != None:
                    self.style[i][self.styledict['Edge width']] = edw
                # change label
                if lab != None:
                    self.style[i][self.styledict['Label']] = lab