Make a mapping from the name=value pairs.

def make_mapping(args):
    """Make a mapping from the name=value pairs."""
    mapping = {}

    if args:
        for arg in args:
            name_value = arg.split('=', 1)
            mapping[name_value[0]] = (name_value[1]
                                      if len(name_value) > 1
                                      else None)

    return mapping