Instantiates a RmlProcessor and registers it in the manager

        Args:
        -----
            name: the name to register the processor
            mappings: the list RML mapping definitions to use
            processor_type: the name of the RML processor to use

def make_processor(self, name, mappings, processor_type, **kwargs):
        """
        Instantiates a RmlProcessor and registers it in the manager

        Args:
        -----
            name: the name to register the processor
            mappings: the list RML mapping definitions to use
            processor_type: the name of the RML processor to use
        """
        from .processor import Processor
        if self.processors.get(name):
            raise LookupError("processor has already been created")
        if isinstance(mappings, list):
            mappings = [self.get_rml(item) for item in mappings]
        else:
            mappings = [self.get_rml(mappings)]
        self.processors[name] = Processor[processor_type](mappings, **kwargs)
        self.processors[name].name = name
        return self.processors[name]