@classmethod<EOL><INDENT>def load_file(cls, filepath):<DEDENT>
obj = cls()<EOL>obj.system = obj._Input.load_file(filepath)<EOL>obj.filename = os.path.basename(filepath)<EOL>obj.system_id = obj.filename.split("<STR_LIT:.>")[<NUM_LIT:0>]<EOL>obj.name, ext = os.path.splitext(obj.filename)<EOL>return obj<EOL>
Create a :class:`MolecularSystem` from an input file.

Recognized input file formats: XYZ, PDB and MOL (V3000).

Parameters
----------
filepath : :class:`str`
   The input's filepath.

Returns
-------
:class:`pywindow.molecular.MolecularSystem`
    :class:`MolecularSystem`