def has_tex():
for exe in ('<STR_LIT>', '<STR_LIT>', '<STR_LIT>'):<EOL><INDENT>try:<EOL><INDENT>which(exe)<EOL><DEDENT>except (ValueError, KeyError):<EOL><INDENT>return False<EOL><DEDENT><DEDENT>return True<EOL>
Returns whether tex is installed on this system

    Checks for ``latex``, ``pdflatex``, and ``dvipng`` on the path.

    Returns
    -------
    hastex : `bool`
        `True` if all required executables are found on the path, otherwise
        `False`