<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def share(self, base=None, keys=None, by=None, **kwargs):
 """ Share the formatoptions of one plotter with all the others This method shares specified formatoptions from `base` with all the plotters in this instance. Parameters base: None, Plotter, xarray.DataArray, InteractiveList, or list of them The source of the plotter that shares its formatoptions with the others. It can be None (then the first instance in this project is used), a :class:`~psyplot.plotter.Plotter` or any data object with a *psy* attribute. If `by` is not None, then it is expected that `base` is a list of data objects for each figure/axes %(Plotter.share.parameters.keys)s by: {'fig', 'figure', 'ax', 'axes'} Share the formatoptions only with the others on the same ``'figure'`` or the same ``'axes'``. In this case, base must either be ``None`` or a list of the types specified for `base` %(Plotter.share.parameters.no_keys|plotters)s See Also -------- psyplot.plotter.share"""

        if by is not None:
            if base is not None:
                if hasattr(base, 'psy') or isinstance(base, Plotter):
                    base = [base]
                if by.lower() in ['ax', 'axes']:
                    bases = {ax: p[0] for ax, p in six.iteritems(
                        Project(base).axes)}
                elif by.lower() in ['fig', 'figure']:
                    bases = {fig: p[0] for fig, p in six.iteritems(
                        Project(base).figs)}
                else:
                    raise ValueError(
                        "*by* must be out of {'fig', 'figure', 'ax', 'axes'}. "
                        "Not %s" % (by, ))
            else:
                bases = {}
            projects = self.axes if by == 'axes' else self.figs
            for obj, p in projects.items():
                p.share(bases.get(obj), keys, **kwargs)
        else:
            plotters = self.plotters
            if not plotters:
                return
            if base is None:
                if len(plotters) == 1:
                    return
                base = plotters[0]
                plotters = plotters[1:]
            elif not isinstance(base, Plotter):
                base = getattr(getattr(base, 'psy', base), 'plotter', base)
            base.share(plotters, keys=keys, **kwargs)