Resolves relative imports from a module.

def resolve_import(import_path, from_module):
    '''Resolves relative imports from a module.
    '''
    if not import_path or not import_path.startswith('.'):
        return import_path

    from_module = from_module.split('.')
    dots = 0
    for c in import_path:
        if c == '.':
            dots += 1
        else:
            break

    if dots:
        from_module = from_module[:-dots]
        import_path = import_path[dots:]

    if import_path:
        from_module.append(import_path)

    return '.'.join(from_module)