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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def replace(self, startpos, args):
 """ Implement printf - based on the stored format specifier information, format the values from the arg getter function `args` into a string. :param startpos: The index of the first argument to be used by the first element of the format string :param args: A function which, given an argument index, returns the integer argument to the current function at that index :return: The result formatted string """


        argpos = startpos
        string = None

        for component in self.components:
            # if this is just concrete data
            if isinstance(component, bytes):
                string = self._add_to_string(string, self.parser.state.solver.BVV(component))
            elif isinstance(component, str):
                raise Exception("this branch should be impossible?")
            elif isinstance(component, claripy.ast.BV):
                string = self._add_to_string(string, component)
            else:
                # okay now for the interesting stuff
                # what type of format specifier is it?
                fmt_spec = component
                if fmt_spec.spec_type == b's':
                    if fmt_spec.length_spec == b".*":
                        str_length = args(argpos)
                        argpos += 1
                    else:
                        str_length = None
                    str_ptr = args(argpos)
                    string = self._add_to_string(string, self._get_str_at(str_ptr, max_length=str_length))
                # integers, for most of these we'll end up concretizing values..
                else:
                    i_val = args(argpos)
                    c_val = int(self.parser.state.solver.eval(i_val))
                    c_val &= (1 << (fmt_spec.size * 8)) - 1
                    if fmt_spec.signed and (c_val & (1 << ((fmt_spec.size * 8) - 1))):
                        c_val -= (1 << fmt_spec.size * 8)

                    if fmt_spec.spec_type in (b'd', b'i'):
                        s_val = str(c_val)
                    elif fmt_spec.spec_type == b'u':
                        s_val = str(c_val)
                    elif fmt_spec.spec_type == b'c':
                        s_val = chr(c_val & 0xff)
                    elif fmt_spec.spec_type == b'x':
                        s_val = hex(c_val)[2:]
                    elif fmt_spec.spec_type == b'o':
                        s_val = oct(c_val)[2:]
                    elif fmt_spec.spec_type == b'p':
                        s_val = hex(c_val)
                    else:
                        raise SimProcedureError("Unimplemented format specifier '%s'" % fmt_spec.spec_type)

                    string = self._add_to_string(string, self.parser.state.solver.BVV(s_val.encode()))

                argpos += 1

        return string