<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def process_docstring(app, what, name, obj, options, lines):
 """React to a docstring event and append contracts to it."""

    # pylint: disable=unused-argument
    # pylint: disable=too-many-arguments
    lines.extend(_format_contracts(what=what, obj=obj))