Merge coordinate variables.

    See merge_core below for argument descriptions. This works similarly to
    merge_core, except everything we don't worry about whether variables are
    coordinates or not.

def merge_coords(objs, compat='minimal', join='outer', priority_arg=None,
                 indexes=None):
    """Merge coordinate variables.

    See merge_core below for argument descriptions. This works similarly to
    merge_core, except everything we don't worry about whether variables are
    coordinates or not.
    """
    _assert_compat_valid(compat)
    coerced = coerce_pandas_values(objs)
    aligned = deep_align(coerced, join=join, copy=False, indexes=indexes)
    expanded = expand_variable_dicts(aligned)
    priority_vars = _get_priority_vars(aligned, priority_arg, compat=compat)
    variables = merge_variables(expanded, priority_vars, compat=compat)
    assert_unique_multiindex_level_names(variables)

    return variables