<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def __fieldNorm(self, fieldName):

 """Normalizes a dbf field name to fit within the spec and the
 expectations of certain ESRI software."""

        if len(fieldName) > 11: fieldName = fieldName[:11]
        fieldName = fieldName.upper()
        fieldName.replace(' ', '_')