def read_asxml(path=None):
    """
    - Reads a big vasprun.xml file into memory once and then apply commands.
    If current folder contains `vasprun.xml` file, it automatically picks it.

    - **Parameters**
        - path     : Path/To/vasprun.xml

    - **Returns**
        - xml_data : Xml object to use in other functions
    """
    if path == None:
        path = './vasprun.xml'
    import xml.etree.ElementTree as ET
    if not path:
        return print('vasprun.xml not found.')
    else:
        tree = ET.parse(path)
        xml_data = tree.getroot()
        return xml_data
