[Python] Dataframe ValueError: The truth value of an array with more than one element is...

I have a dataframe (reportingDatesDf) which the head looks like this:

reportingDatesDf.index unique_stock_id reporting_type
date
2015-01-28 BBG.MTAA.STM.S 2014:A
2015-01-28 BBG.MTAA.STM.S 2014:S2
2015-01-28 BBG.MTAA.STM.S 2014:Q4
2014-10-29 BBG.MTAA.STM.S 2014:C3
2014-10-29 BBG.MTAA.STM.S 2014:Q3


I am trying to reduce the dataframe to include entries that are only between 2 dates with the following line:

reportingDatesDf = reportingDatesDf[(reportingDatesDf.index >= startDate) and (reportingDatesDf.index <= endDate)]


The dataframe is created from a CSV using the following code:

def getReportingDatesData(rawStaticDataPath,startDate,endDate):
pattern = 'ReportingDates'+ '.csv'
staticPath = rawStaticDataPath

with open(staticPath+pattern,'rt') as f:

reportingDatesDf = pd.read_csv(f,
header=None,
usecols=[0,1,2],
parse_dates=[1],
dayfirst=True,
index_col=[1],
names=['unique_stock_id','date','reporting_type'])
#print(reportingDatesDf.head())
print('reportingDatesDf.index',reportingDatesDf)
reportingDatesDf = reportingDatesDf[(reportingDatesDf.index >= startDate) and (reportingDatesDf.index <= endDate)]


I however get the error:

ValueError: The truth value of an array with more than one element is ambiguous. Use a.any() or a.all()
​

Why has this happened? I am using similar code elsewhere which works.

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