from pyparsing import *

indentStack = [1]
stmt = Forward()
suite = indentedBlock(stmt, indentStack)

funcDecl = "def" + Word(printables)
funcDef = Group( funcDecl + suite )

stmt << ( funcDef | "open" | "close")
module_body = OneOrMore(stmt)

code="""
def process
    open
    close"""

funcDef.parseString(code)  ### works fine
funcDef.parseString(code)  ### throws excepotion

pyparsing.ParseException: not a subentry (at char 16), (line:2, col:5)