def trim_docstring(docstring):
    """
    Uniformly trims leading/trailing whitespace from docstrings.

    Based on http://www.python.org/peps/pep-0257.html#handling-docstring-indentation
    """
    if not docstring or not docstring.strip():
        return ''
    # Convert tabs to spaces and split into lines
    lines = docstring.expandtabs().splitlines()
    indent = min([len(line) - len(line.lstrip()) for line in lines if line.lstrip()])
    trimmed = [lines[0].lstrip()] + [line[indent:].rstrip() for line in lines[1:]]
    return "\n".join(trimmed).strip()